China's Communist Party issued a soul-searching document today, concluding that its late chairman Mao Tse-tung committed serious errors during his last 20 years, although his lifetime contributions outweigh his mistakes.

The report drafted by the Central Committee after months of divisive debate also criticizes the party for failing to check Mao's power, condemns Mao's Cultural Revolution, rebukes his handpicked successor and places the party's imprimatur on the reform measures guiding China today.

But the most significant sections of the 119-page document deal with Mao's legacy, the first time China's fractious leadership has rendered an "official" judgment on the man who founded the Chinese Communist Party 60 years ago, led it to victory in 1949 and then ruled the nation until his death in 1976.

Coming as it does a day before the party's 60th anniversary and a day after the naming of a new party chairman, the document was being hailed by Chinese officials as a seminal treatise that achieves the necessary purging of past mistakes to set a proper course for the future.

Along with last night's demotion of Mao's chosen successor, Hua Guofeng, and the trial and jailing last January of Mao's wife, the document is an unmistakable signal to leftist opponents of new pragmatic programs to forget about Maoism as an alternative strategy.

Although the report criticizes Mao for policies as far back as 1957, it saves its harshest censure for the "gross mistakes" he made in leading the Cultural Revolution, a disastrous 10-year campaign aimed at reinjecting revolutionary vigor into a party Mao felt had grown slothful and decadent.

The movement that persecuted thousands of party officials and threw the nation into chaos before it ended in 1976 "was responsible for the most severe setback and heaviest losses suffered by the party, the state and the people since the founding of the people's republic," the document said.

"It was initiated and led by comrade Mao Tse-tung," it aserted, adding that Mao "must be held chiefly responsible" for the ensuing tragedy.

Although Mao has been chided by the official press and some politicians for his role in the Cultural Revolution, never before has a ruling body with the status of the 195-member party Central Committee united behind a criticism of the man known at the time as "the great helmsman."

A consensus on the issue has been extremely difficult to achieve because a large number of officials still in the military and bureaucracy prospered during the upheaval and fear that a condemnation of Mao's role, in effect, jeopardizes their positions.

Although even the most loyal Maoists were willing to concede in general terms that the Cultural revolution had been a disaster, they resisted moves to criticize specific incidents that could have exposed their own roles, according to diplomatic sources with good Chinese contacts.

Countering this so-called leftist bloc were those who had suffered grievously -- intellectuals, scientists and veteran cadres, including some associated with the pragmatists now running China -- who sought a detailed censuring of Mao for stunting the nation's political and economic life.

The document issued today represents a compromise, reproaching Mao for his "entirely erroneous appraisal" of China's political situation at the time, for "his personal arbitrariness" that shut out debate in the party and for giving power to his wife, Jiang Qing, and her "Gang of Four" associates.

But the criticism stops short of analyzing specific events and concludes that Mao's Cultural Revolution "was the error of a great proletarian revolutionary . . . who confused right and wrong and the people with with enemy."

Noting his success as a liberation fighter, founder of the party and the author of a Marxist theoretical school, the document said, "If we judge his activities as a whole, his contributions to the Chinese revolution far outweigh his mistakes. His merits are primary and his errors secondary."

The Central Committee, the party's most important representative body, further mitigated Mao's role by shifting partial blame to the party itself. It said the party had failed to stop "overconcentration of power" and "the development of arbitrary individual rule."

In an extraordinary self-criticism for a ruling communist government, the report asserted that "our party has both the courage to acknowledge and correct its mistakes and the determination and ability to prevent repetition of serious mistakes of the past. It is impermissible to overlook or whitewash mistakes, which in itself would be a mistake and would give rise to more and worse mistakes."

The report said the party also shared Mao's blame for errors dating back to the 1950s, including the "anti-rightist" campaign of 1957 that "unjustifiably" persecuted party intellectuals and the crash economic program of 1958 known as the Great Leap Forward that resulted in huge economic losses and mass starvation in depressed rural areas.

In its spirit of open criticism, the Central Committee turned to the man Mao chose as his successor in 1976, Hua Guofeng, who stepped down as chairman last night in favor of a reformer, Hu Yaobang. Hua assumed the job of junior vice chairman, ranked seventh in the party hierarchy.

According to the report, Hua erred by slavishly following Mao's policies, trying to suppress the emerging pragmatic views, obstructing the rehabilitation of public officials persecuted during the Cultural Revolution, promoting unrealistic economic goals and trying to build his own cult of personality by parroting Mao.

"Obviously, under his leadership it is impossible to correct . . . errors within the party and all the more impossible to restore the party's fine traditions," said the report, which was drafted before Hua "resigned" as chairman.

On the other hand, the modernizers and party reformers who forced out Hua, were applauded in the report for adopting "correct policies" and creating an environment where "all aspects of party and government work have been flourishing again . . . and the road of victorious advance is open."