The People's Republic of China took its place as a member of the World Bank and International Monetary Fund yesterday with a speech by Wang Bingqian, the Chinese minister of finance, pledging that the Socialist nation would give "full play to the positive aspects of a market economy."

Stressing that China had not yet recovered from "a decade of chaos" that ended in 1976, Wang said that "we are going to give the enterprises a greater say in running their own affairs, and we will apply the economic leverage exercised through fixing prices, setting taxes and interest rates and having recourse to bank credits under the overall guidance of state planning."

He also promised that China would try to develop foreign trade, import foreign capital and expand economic cooperation with other countries. Perhaps in recognition that some American companies reportedly have been discouraged about the prospects for doing business in China because of the abandonment of a projected $250 million foreign trade center, Wang said:

"This [cooperative policy] is not a makeshift measure but a long-term policy that we will be following." He noted that China now has established correspondent relationships with 975 banks in 144 countries and is in the process of drafting "relevant economic legislation to guarantee the legitimate rights and interests of foreign investors and collaborators."

But having made his bow to the freemarket-oriented leaders of the International Monetary Fund and World Bank, Wang promptly lined China up with the Third World bloc pressing for major changes in both institutions.

"The international monetary system established at Bretton Woods [Imf and World Bank] can no longer meet the needs of our new conditions and must be reformed so as to bring about the early establishment of a new, equitable and rational international monetary system."

Wang was not specific. But he made a point of congratulating Amir Jamal, the Tanzanian minister of finance who is chairing the meeting, for his Tuesday speech which was bitterly critical of both the IMF and the bank. Wang said he had listened "with interest" to the remarks of President Carter and others who had urged a liberalization of the bank and IMF lending policies but who endorsed the existing structure of the institutions.