The incoming Republian chairman of the Senate Judiciary Committee is considering abolishing a 25-year-old subcommittee that has been one of the main platforms in Congress for criticism of big business.

The targeted panel is the antitrust and monopoly subcommittee. Its chairmen in the past have included Estes Kefauver, Philip A. Hart, and Edward M. Kennedy. In line to be its chairman in next year's Republican-run Senate would be Judiciary's second-ranking Republican, Charles McC. Mathias of Maryland. He is part of the liberal-to-moderate wing of his party and far less conservative than Judiciary's chairman-to-be, Strom THURMOND (S.C.).

If Thurmond could merge the subcommittee into full Judiciary, as he is considering doing, he would retain control over business-sensitive antitrust issues while remaining free to head the subcommittee on the Constitution. That panel will deal with proposed constitutional amendments he favors, such as those on abortion and school busing. As Judiciary chairman he can head only one subcommittee.

But Thurmond, who could not be reached for comment, faces resistance from outgoing antitrust chairman Howard M. Metzenbaum of Ohio.

"I think it would be a travesty and an embarrassment to the incoming Republican administration to abolish the antitrust subcommittee," he said in an interview. "Antitrust is not a Democratic program -- it was actually authored by Sen. John Sherman of Ohio, a Republican."

Major antitrust cases were vigorously pressed in the Eisenhower and Nixon administions.

For a quarter-century, the antitrust subcommittee put investigative spotlights on merger movements and anticompetitive practices -- such as price-fixing and monopolization -- in a wide range of industries -- automobile, bread, broadcasting, computer, credit, drug, electrical equipment, health, insurance, newspaper, oil, steel, telecommunications, utilities.

Former chairman Kefauver held celebrated hearings on the drug industry, exposing stunning price markups; Hart of Michigan took the unusual step for a senator of hitting at a home-state power with his 1974 hearings on the need to restructure the auto industry to make it more competitive. Kennedy and Metzenbaum sponsored a 1979 bill to bar the 16 largest oil companies from acquiring any firm with assets exceeding $100 million.

Thurmond first hinted at the possibility of merging jthe antitrust subcommittee out of existence in a post-election press conference. Some Senate staff members say he has told at least one colleague -- in writing -- that he intends to recommend to the committee, at its organizational meeting in January, that it take over the subcommittee's functions, which include monitoring enforcement of the antitrust laws by the Justice Department and the Federal Trade Commission. A new chairman's recommendations in such matters are almost invariably followed.

A Republican staff member of Judiciary recalled that Thurmond, at the press conference, described the antitrust area as being of such importance that it deserves the attention of the full committee.

Asked if the important of the area wasn't what led to the formation of the subcommittee, the source, who asked not to be named, said, "That was 25 years ago."

He also said that subcommittees can serve as camouflaged dumping grounds for controversial legislation and that many Judiciary members favor abolishing antitrust because they would have a chance "to become involved" in antitrust actions more quickly.

"I can assure you that it [the full committee] will be very active" in antitrust matters, the staff member said. "They would not be on a back burner,I assure you."

At the same time, the source insisted that Thurmond has not made up his mind. "I don't know which way he'll go on this thing," he said.

Metzenbaum told a reporter that abolition of the subcommittee "would send such a negative message to the American people, because antitrust means nothing more than permitting the free enterprise system to work effectively. It is the engine of free competitive forces. . . . "