The chairman of the Senate education subcommittee said at a law school in Vermont that William J. Bennett "would not be the secretary of education" if he had made his recent remarks on college student aid before his confirmation hearing.

Sen. Robert T. Stafford (R-Vt.) was quoted in yesterday's Rutland Daily Herald as saying, "If I knew he would make these kinds of statements, he would not be the secretary of education."

Bennett could not be reached for comment last night.

At a news conference on Monday, his first as education secretary, a combative Bennett told reporters that he would "actively" support President Reagan's proposed college aid cuts, the most important of which would deny aid to students from families earning more than $32,500 a year. He said students hurt by the cuts should consider "divestiture of certain sorts -- stereo divestiture, automobile divestiture, three-weeks-at-the-beach divestiture."

Bennett also emphasized that he was not speaking under duress. "The notion that I am here somehow under coercion . . . is simply counterfactual," he said.

By contrast, during his confirmation hearings, he generally sidestepped the aid issue, telling one senator, "I would look forward to working with the committee to talk about this, to see if a different figure could be, or should be, arrived at."

Sen. Edward M. Kennedy (D-Mass.), ranking Democrat on the Labor and Human Resources Committee, said yesterday through a spokesman, "At the time he appeared before the committee, he was not frank, he was not forthcoming in his view on these cuts."

The Reagan plan, estimated to knock a million students off the federal college aid rolls, would also set a $4,000 "mega-cap" on all forms of federal aid.