Looking calm and confident, television evangelist Jerry Falwell said today he believes that his $45 million libel suit against publisher Larry Flynt will be a test "as to how far a sleaze merchant can go in damaging someone's reputation and character without paying for it."

Falwell's remarks came during a recess shortly before attorneys for Falwell, Flynt and Flynt's sex-oriented Hustler magazine presented opening arguments to an eight-woman, four-man jury that is hearing the case here in U.S. District Court. The trial, which Falwell's attorney has called "a pitched battle between the forces of good and evil," is expected to last all week.

At issue is a one-page parody of a liquor ad that appeared in the magazine, which Falwell contends damaged his reputation and emotional well-being.

Flynt has filed a countersuit against Falwell alleging that he used the parody without authorization in a fund-raising effort.

The ad described Falwell as having an incestuous relationship with his mother and it carried a line describing it as a parody and "not to be taken seriously."

Today, Flynt lawyer Alan L. Isaacman told the jury that Hustler had parodied a well-known ad for Compari liquor, using "someone who no one in a million years would believe would drink Compari and have sex with his mother."

Falwell disagreed and his attorney, Norman Roy Grutman, the New York lawyer who successfully defended Penthouse magazine after Falwell sued it for $10 million in 1981, gave an emotional presentation to the jury.

Grutman said that the ad was intended to destroy Falwell's reputation and thus his multimillion-dollar evangelical empire.

"They launched that swill, they published it, and Mr. Flynt will admit that what he had in his heart was nothing but contempt and unmitigated ill will. He wanted the world to believe that interview in the ad was true."

Grutman said Falwell depends on his reputation to do business, adding that "the ministries of Jerry Falwell would be dead and paralyzed if anyone began to doubt that Jerry Falwell is the man who he says he is."

The trial is playing to a packed courtroom and promises some unusual courtroom drama.

Falwell's team of three attorneys plans to show a videotaped deposition from Flynt in which they claim that the publisher says he believes the parody to be a statement of fact.

Flynt's attorneys today countered that Flynt gave the deposition while medically disabled by drugs and pain.

Both Falwell, leader of the religious right and founder of the Moral Majority, and the wheelchair-bound Flynt, who has called himself the "Duke of Raunch," are expected to testify.

The 50-year-old Falwell is a self-described teetotaler whose base is the huge Thomas Road Baptist Church and Liberty Baptist College in nearby Lynchburg.

Flynt, 41, has been in a wheelchair, paralyzed from the waist down since he was shot in 1978 in Lawrenceville, Ga., while attending a trial on obscenity charges. A former Kentucky farm boy with a grade school education, Flynt has built a multimillion-dollar empire that includes magazines, a lucrative magazine distributorship and a sex products mail order business.