Howard University President James E. Cheek, taking a firm line against student protesters, said yesterday that the university would press ahead with efforts to expel the editor of the campus newspaper and called charges against his administration "a lot of student rhetoric."

Cheek, who has been president of Howard for 13 years, strongly denied conducting "a witch hunt" against the ousted editor, Janice McKnight, who was temporarily reinstated by a D.C. Superior Court judge last week.

But in an interview in his office, Cheek said that when a new hearing is held in the case, the university will seek to uphold the expulsion.

The decision to expel McKnight, a 23-year-old senior, touched off a series of student demonstrations calling for Cheek's resignation, including a lunchtime rally yesterday. But last Friday's plans for a student boycott were sidetracked by the blizzard, which forced the cancellation of classes. Student leaders said they were uncertain yesterday when a boycott might be held.

In the interview, Cheek said, as other Howard officials have said, that the expulsion of McKnight occurred because she gave untruthful information in her admissions application in 1979, concealing the fact that she withdrew from Syracuse University "not in good standing" before applying to Howard.

Cheek said Howard did not expel her because McKnight disregarded his request to stop publishing what he said were "potentially libelous" articles on a sex discrimination complaint against the university's general counsel, Dorsey Lane.

"We only discovered this [omission in McKnight's application form] inadvertently in compiling information [on the newspaper controversy] for the university board," Cheek explained. "To have swept it under the rug would have been an act of dishonesty on our part."

Cheek said McKnight violated a signed pledge of truthfulness at the bottom of the application form, and would have been "ineligible" for admission if she had disclosed her record at Syracuse. He said she was treated the same way as three other students about whom the university discovered similar information.

If McKnight had not been expelled, Cheek said, "we would have become a party to the perpetration of a fraud."

In her lawsuit, McKnight, who has a B average at Howard, contended that she was expelled for printing the articles about the sex discrimination complaint. She said the university had violated its own rules by not granting her a formal hearing. Judge George H. Goodrich said it was "a mighty strange coincidence" that the expulsion followed other university efforts to stop the articles.

McKnight was expelled on Feb. 1, one day after the university fired Michael Harris, the staff attorney who had filed the charge with the Equal Employment Opportunity Commission that Lane favored female employes in pay and promotions.

Since then, a university attorney and other officials have explained the university's decisions, but except for a brief appearance at a student rally Cheek himself has issued no statements and has turned down requests for interviews. Yesterday, a university spokesman asked several reporters to come to Cheek's office.

The university president said he was not prepared to talk about the wide range of student complaints, which include censorship, poor housing, crime on campus, an "insensitive" bureaucracy, and Cheek's occasional praise for President Reagan. Contrary to one student charge, Cheek said Howard does not intend to end its deferred payment plan, although a vice president had earlier proposed that the university do so.

The campaign against him, Cheek said, was "a lot of student rhetoric." He said most of it came from Howard Newell, president of the university Student Association.

Cheek, 50, recalled that he himself had been an editor of student newspapers and a campus leader both in high school in Greensboro, N.C., and at Shaw University. He said he was expelled from high school by a principal who falsely accused him of organizing a strike by a high school band.

Cheek said he told McKnight,"I understand that you as editor have to make decisions."

But he added: "In a private institution, when the institution provides financial and other support for the student newspaper, the university is the publisher, and First Amendment rights of freedom of the press belong to the university, not to the newspaper."

Cheek said he has known Harris "extremely well" since the attorney was a student leader at Howard in the late 1960s. But he said Harris' charges of sex discrimination have "no merit."

In one charge, Harris declared that Lane has a "personal and special relationship" with Brenda D. Williams, who was promoted to be Lane's special assistant at $2,000 more a year than the $29,0000 Harris was paid. Harris included with his EEOC complaint a copy of a document showing that Lane was coborrower with Williams on a $79,300 loan to buy a condominium in Silver Spring.

"What her relationship is with Mr. Lane I don't know," Cheek said. "That was irrelevant. Whatever the relationship may be, the question was, 'Did she get salary increases and promotions because of her relationship with Mr. Lane?' The answer to that is 'no.' She was qualified."