A new study of the potential of the Chinese economy under its present political leadership foresees a continuation of rapid economic growth to the point where China would become the fifth strongest power in the world by the year 2000, with a gross national product fully half that of the United States.

At the same time, the study cautions that economic progress in the Peoples' Republic is "extremely vulnerable" because of potential internal political disruption.

"No one can predict, for example, whether the policies of modernization will be able to survive the passing of the 73-year-old (Deputy Premier) Teng Hsiao-ping, generally regarded as the instigator and implementor of China's push for modernization," the report says.

China's new drive for industrial modernization has been evidenced recently in the broad-scale commercial, cultural and other contacts with the Western World, a turn-about from Mao Tse-tung's policy of self-reliance and near isolation.

The new study was produced for the Joint Economic Committee of Congress by 37 scholars from academic institutions in the U.S., Canada, the U.K., Sweeden and some departments of the U.S. government.

Two of the authors, Robert E. Dernsberger and David Fasenfast, predicted a "tremendous potential" for economic growth." They believe that, under the Teng leadership, there is the probability of a "considerable degree of success."

However, Nicholas P. Lardy points out that 5.5 percent annual-G-P and 9 percent industrial growth - goals of the 10-year plan announced two years ago - may not be achieved because of disappointing performance in 1976 and 1977.

This sluggish pace probably "figured in the decision" to restore Teng, who was purged by Mao, to his position in the party and the government.

Many of the authors closely tie a continuation of recent favorable trends - from the West's standpoint - to Teng and the maintenance of his power. Although recent events, especially the open criticism of Mao, would seem to enhance Teng's role, one of the principal authors of the report warns of a new shift in political power.

William W. Whitson says that "in light of the past 25 years of change in China, the odds seem to favor such a shift in Chinese political style before 1980, probably having the effect of constraining the authority to central leadership, increasing the role of the military both in Peking and the provinces, accelerating military modernization with a consequent delay in the achievement in economic goals, and bring(ing) another round of domestic political instability."

Mai-Ruenn Chen adds that " a group of 'neo-radicals' (may rise) to seriously challenge the pragmatic leadership" of the post-Mao era.

The report says that, although Chinese leaders aim to develop a powerful industrial state capable of dealing with the existing superpowers, they are not following "the Stalinist-type urgency to overtake and surpass the West" in a short time period.