Two sets of influential Republican senators are battling for President Reagan's ear in a widening dispute over Chinese textile quotas that has become entangled with American wheat sales to Peking.

"Chinese officials have made it clear they aren't buying our wheat because of the quota dispute," Sen. Robert J. Dole (R-Kan.) wrote yesterday in a letter urging Reagan to break the impasse in a seventh round of U.S.-Chinese textile talks scheduled to start Monday in Geneva.

An aide to Dole, chairman of the Senate Finance Committee, said the dispute has cost U.S. farmers more than $500 million in lost wheat sales to China so far this year.

"Every time a Chinese official on a wheat buying mission passes through this country on the way to Buenos Aires, they thumb their noses at us and ask when we are going to settle the textile problem," the Senate aide said.

The battle for Reagan's attention pits Dole against Sens. Jesse Helms (R-N.C.) and Strom Thurmond (R-S.C.), who, according to official sources, have urged the president to postpone next week's Geneva talks.

A delay would permit a special White House committee to complete its study on textile imports. The committee is believed by retailers and farm sources to be weighted in favor of tightening quotas on textile imports, which the industry complains have soared by 21 percent so far this year.

The dispute, moreover, has split the Republican majority on the Senate Agriculture Committee between wheat state members such as Dole and senators from textile states such as Thurmond and Helms.

It also has caused added problems for Helms, the committee chairman, who angered some members last year with his nearly total preoccupation with textile and tobacco issues dear to his North Carolina constituents, to the exclusion of issues important to the majority of American farmers.

Dole, in his letter to Reagan, said the cost to the textile industry because of any increase in Chinese imports doesn't come close to matching the lost sales of farm products to China, which is the United States' biggest wheat buyer. Chinese textile sales to the United States last year amounted to $750 million, about three-fourths of the total wheat sales.

"Any benefit of further delay," Dole wrote the president yesterday, "cannot possibly outweigh the cost being paid by U.S. wheat farmers."

American trade sources said Monday's talks will go on unless Reagan personally intervenes to stop them.

But representatives of clothing retailers, who oppose tight quotas, expressed the fear that textile industry pressure during the negotiations will force a continued stalemate.

Winston Williams, president of the U.S. Wheat Associates, said the United States generally supplies about 7 million tons of China's total wheat purchases of 10 million tons a year.

Since the impasse over textile quotas broke out in January, however, "They haven't bought a grain. There have been zero new purchases. We've lost 4 million tons to this point," he said.

"The Chinese have clearly linked the textile situation to their agricultural purchases," added Julian B. Heron Jr., chairman of the U.S. Agricultural Export Development Council.

Besides Argentina, the Chinese have been buying wheat from the European Economic Community, expecially France, whose Agriculture Minister, Michel Rocard, visited Peking last week at the request of Chinese Agriculture Minister He Kang.

U.S. trade sources said the French just completed a sale of 1 million tons of soft wheat that China usually buys from the United States.

The Chinese--trying to break into world textile trade alongside the current big three suppliers, Hong Kong, South Korea and Taiwan--asked for increased quotas from the United States while the Reagan administration wants to link any growth in imports to increases in the domestic market.

Dole attacked that administration policy as "a principle that could have severe negative effects if applied to our own exports."

In a budding dispute, meanwhile, the government of Hong Kong formally protested the possibility that the United States will place immedate embargoes on further textile imports from the crown colony.