Vice President Hu Jintao, who by exercising extreme caution has survived a decade as heir apparent to the Chinese Communist leadership, rose to the pinnacle of power in Beijing today in the most orderly and peaceful transition in the history of modern China.

In a ceremony rich with Communist pageantry, the 59-year-old hydrologist, known for his powerful memory and colorless personality, was appointed general secretary of the Communist Party. But President Jiang Zemin, 76, who formally stepped down Thursday as party chief after 13 years in power, is expected to continue to exert influence in retirement.

Hu's rise to China's top post, which was sealed at the week-long 16th National Congress of the Communist Party, was part of a broad transfer of power, ushering in a new generation of leaders as the country undergoes enormous social and economic change, and leaves behind the doctrinaire communism upon which Mao Zedong founded the party's rule in 1949.

Hu, dressed in a blue suit and red tie, and his eight new colleagues on the Standing Committee emerged from behind a screen emblazoned with two cranes, a Chinese symbol of longevity, in the cavernous Great Hall of the People just off Tiananmen Square. The committee's new makeup was a testimony to the enduring political strength of Hu's predecessor, Jiang, who succeeded in placing six of his closest allies onto the body and expanding it by two seats.

Surrounded by Jiang's men, Hu will probably need years to secure his position as the most powerful man in China, if he does at all.

"The meeting was very successful," Hu said. "The congress was one of unity, victory and endeavor. It has built on the past and will carry our cause into the future. . . . We won't let the Chinese people down."

State-run television showed delegates to the congress voting for the party's new Central Committee, which then was said to have voted for the Politburo and its all-powerful Standing Committee. But in fact, all decisions were made in secret by a handful of men and revealed officially only this morning as the winners filed onto a stage to address journalists.

Hu is relatively young for China's senior-most office. He will complete his assumption of leadership next March during a session of the National People's Congress, or parliament, when Jiang is to resign as president and make way for Hu to succeed him in that job as well. However, the party announced today that Jiang was reelected chairman of the party's Central Military Commission, a powerful platform from which he can continue to wield influence.

All six of Hu's former Standing Committee colleagues retired yesterday, as did seven other aging members of the 22-member policy-making Politburo. In addition, more than half the 356 voting and alternate members of the Central Committee departed. Generals of the People's Liberation Army over the age of 70 on the Central Committee stepped down as well, presaging a reshuffle at the top of the world's largest army. And several senior ministers left the committee, signaling important changes in the Chinese cabinet when the legislature meets next March.

The men who won the top party jobs are all engineers, men in their fifties or sixties who came of age in Mao's destructive Cultural Revolution and rose to powerful positions in Beijing and the provinces after the 1989 crackdown on pro-democracy protests in Tiananmen Square. They appear committed to the capitalist-style economic reforms that have brought unprecedented prosperity to the world's most populous nation, and to maintaining good relations with the United States.

They also appear determined to preserve the Communist Party's tight grip on all aspects of political life in China. But at least one corporate executive, Zhang Ruimin, president of the Haier appliance company, which owns a building in Manhattan and is listed on the Shanghai Stock Exchange, won a seat as an alternate on the Central Committee. That was seen as another sign of the party's increasing tilt toward business and away from promoting the interests of China's dispossessed.

Chinese sources and analysts said Hu will face serious challenges as he attempts to exert control over the party in the coming years. Jiang completely dominated the congress; Hu made no major speeches.

Among Jiang's six allies on the Standing Committee is his top aide, Zeng Qinghong, 63, a skillful political operative and the official most responsible for helping Jiang defeat his enemies and hold on to power over the past decade. Analysts said Zeng is Hu's only potential rival in the new leadership; some believe Jiang may eventually attempt to install him in the top job.

Hu is described as a talented and intelligent leader with a photographic memory. But it was Deng Xiaoping, Jiang's predecessor, who made him the Standing Committee's youngest member in 1992 and set him up as Jiang's natural successor. Hu has been so careful not to offend Jiang or make mistakes in the years since that few know where he might lead the nation.

Before joining the Standing Committee, Hu served as the party secretary in Tibet, where he approved the imposition of martial law to crush a wave of protests in March 1989.

"What happens to this leadership depends on what kind of relationship emerges between Hu and Zeng," said Cheng Li, a political scientist at Hamilton College in Clinton, N.Y., who has studied the new generation of leaders. "Their relationship has been both competitive and cooperative up to now, and for the next few years, they will be trying to consolidate their bases of power."

As a result, few changes in the party's basic policies are expected in Hu's first years.

Among other winners in the senior leadership were conservatives such as Luo Gan, 67, the security chief best known for leading a nationwide crackdown on crime that has relied heavily on executions, and Wu Guanzheng, 64, a Jiang ally and party chief of eastern Shandong province, where a violent campaign to suppress the banned Falun Gong spiritual movement has resulted in scores of deaths.

Still, some in the government and state-run media hope Hu and other Standing Committee members, including Zeng and the man expected to be named premier, Wen Jiabao, 60, may be willing to experiment with limited political reforms as the influence of the older generation fades.

Jiang's departure marked the end of an era in Chinese politics that began with his promotion to party chief after the Tiananmen Square crackdown. During his tenure, China moved from 10th in the world in gross domestic product to sixth, and many Chinese enjoyed unprecedented prosperity and personal freedom. The country's international profile rose enormously. Last year it joined the World Trade Organization and Beijing was awarded the 2008 Olympic Games.

But the Jiang era was also characterized by successive crackdowns on political dissent and religion, a widening gap between rich and poor, and corruption that rivals that of the Nationalist government that ruled China before the 1949 Communist Revolution.

To the dismay of some Chinese, one man who won a seat on the Standing Committee is Jia Qinglin, 62, an old friend of Jiang's who served as party chief in Fujian province in the mid-1990s when a multibillion-dollar smuggling ring flourished there. In November 1999, as that scandal was being uncovered, Chinese officials in Beijing contacted Western journalists and accused Jia and his wife, Lin Youfang, who ran Fujian's main state-run import-export corporation, of being involved. A month later, however, Jiang moved to protect Jia.

Three other Jiang loyalists on the Standing Committee are Li Changchun, 58, the party official who governed in freewheeling Guangdong province in the south; Wu Bangguo, 61, a deputy premier and longtime aide to the former general secretary; and Huang Ju, 64, the former party chief of Shanghai.

In addition to ushering in a new generation, this week's congress set out a new goal for the Communist Party: building a middle-class nation with a per-capita income of $3,000 by 2020. In a sign of the waning appeal of Marxist ideology, Jiang used terminology from the country's 2,500-year-old "Book of Songs" to describe the mission, saying the party would build a society reflecting the Confucian ideal of a prosperous, peaceful community.

The congress also enshrined Jiang's political philosophy in the party constitution, adding a reference to the "Three Represents." The theory argues that the party should represent China's businessmen, entrepreneurs and other "advanced productive forces," not just workers and farmers. The party constitution was rewritten to allow them to become members.

Hu Jintao, left, and other members of the new Chinese leadership greet reporters at the Great Hall of the People in Beijing, where the Communist Party's 16th National Congress met in a week-long session and elevated a younger generation to power. Hu Jintao, 59, is described as a talented and intelligent leader with a photographic memory.