Regardless of internal arguments and eventual leadership changes, the main lines of China's modernization program are likely to endure, in the view of Arthur W. Hummel Jr., the China-born U.S. ambassador here.

Hummel, in an interview, said that given the difficulty of the modernization task, "zigs and zags" resulting from mistakes and from arguments over the pace and side effects of the economic reforms are inevitable.

But he predicted that the essential lines of the program will continue, "no matter whether the present leadership dies tomorrow, is replaced, or whatever, because there is a very deep conviction that China is very far behind its neighbors, that China needs to modernize its whole economy and also modernize its society in some ways."

There is also a conviction, he said, that modernization has to be carried out with the help of foreign capital and technology as well as with the help of some outside managerial skills.

Arguments within Chinese society over the disruptions, apparent inequities, and illegal financial dealings on the part of some Chinese that have accompanied the modernization are evident in speeches of Chinese officials and in the press.

Official pronouncements on the need to counter corruption and instill new discipline have caused some foreigners to fear that the modernization program might be slowed, if not reversed. But recent indicators tend to confirm Hummel's prediction that the reforms will continue.

On March 24, the official New China News Agency reported that Document No. 1 for 1985 of the Communist Party's Central Committee sets out 10 measures aimed at encouraging "a market-oriented rural economy." The agency confirmed that China was going ahead with plans disclosed earlier this year to revise the system of compulsory state purchases of agricultural produce.

According to the document, "The responsibility system that links income with output . . . will remain unchanged for a long period to come."

At the same time, People's Daily, the official Communist Party paper, addressed the concerns of some of the critics of the modernization program, saying that "in the world there is nothing that is perfect" and that some problems are unavoidable. In its front-page weekly commentary, the paper said that one should not give up the overriding advantages of the program just because it entailed some disadvantages.

People's Daily said the confidence of "some people" in the changes had declined compared with the last quarter of last year. But with China's "open-door" policy, the paper said, "it is unavoidable that some pernicious capitalistic ideas will enter China."

"Some Chinese wonder whether they're going too fast," Hummel said. "Some wonder whether the social disruptions are more than China should have. Some ask whether it's a good idea to allow -- temporarily, they say -- some people to get rich while others are still poor."

Calling such disputes "perfectly natural," Hummel said: "There must be arguments about how to do it, because there is no recognized model for having a portion of an economy still under state control . . . and having a general socialist system here while at the same time releasing the provinces and cities to make their own decisions outside the central plan and allowing market forces to determine at least in part the way prices work."

"It's a very delicate thing to do to try to reduce the terrible subsidies that take up more than 40 percent of China's budget," he said. "It obviously means that consumers have got to pay more. . . . This means that prices have to go up, and the leadership has squarely recognized the fact and is going to take care of it by having wages go up also."

"So there will be zigs and zags," he said. "There will be mistakes, perhaps very conspicuous ones, that will cause the central government to pull back in its pace of reform. There will be successes, too, that will cause them to move a little faster.

"There will be complaints and arguments, . . . but the main trend, the main lines of the modernization drive, I'm quite confident, are going to continue."

Hummel, a former ambassador to Pakistan, is the first career diplomat to head the U.S. mission in China since a liaison office was set up here in 1973. He was appointed ambassador in August 1981, succeeding ex-union leader Leonard Woodcock.

Hummel was born in Shanxi Province in 1920, the son of a Congregationalist minister and noted Sinologist.

In 1941, when Japan attacked Pearl Harbor, Hummel was teaching in Peking. He spent two years in a Japanese prison camp, escaped with help of Nationalist Chinese guerrillas, joined them, and for the next 15 months fought the Japanese.

After the war he worked for a year as a U.N. relief officer, surveying Communist-controlled areas of China's northeast. He later earned a graduate degree in Chinese from the University of Chicago and joined the State Department in 1950.