Television preacher Jerry Falwell came to the Capitol steps yesterday to attack President Carter, homosexuality, pornography, television comedies, abortion, discos, divorce and sex education before 8,000 flag-waving supporters shouting "Amen" and singing "God Bless America."

Pastor of a 16,000-member Baptist church in Lynchburg, Va., and head of a multimillion-dollar religious broadcast empire, Falwell was flanked by a handful of conservative congressmen at the noontime rally.

Thrusting his large frame before the television cameras, the 45-year-old evangelist vowed to stamp out "the national cancers degrading the Republic" as part of his campaign to "Clean Up America."

Falwell called sex education textbooks "Soviet propaganda" and attacked the Internal Revenue Service for attempting to remove the tax-exempt status of religious schools.

Approximately 8,000 students from 156 Christian schools around the country were bused to Washington for the event, which was taped for a national television broadcast over the 317 stations that carry Falwell's "Old Time Gospel Hour."

The students waited for two hours under a canopy of umbrellas singing hymns before the soft spring shower suddenly ended as Falwell took the microphone.

"If the Capitol were on fire, we'd still be here," Falwell shouted, before passing out thousands of silver colored lapel pins bearing the slogan, "Jesus First."

Pointing to the students, Falwell told congressmen he was proud of the neatly dressed crowd. "You can tell the boys from the girls with out a medical examination," the chubby faced preacher said. "They are dressed as they should be in the presence of royalty."

Falwell emphasized that yesterday's demonstration was not a political rally despite its location and the presence of eight legislators, who shared Farewell's pulpit. Sen. Paul Laxalt (R-Nev.), wearing handtooled cowboy boots, told the crowd that he was raised as a conservative because his parents "knew the Holy Bible."

"I'll stand with Jerry Falwell anytime," agreed Sen. Jesse Helms (R-N.C.). "I know where Jerry's strength comes from."

Much of that Strength seems to be in numbers.Falwell's programs are carried on radio and television to an estimated audience of 10 million. Last year, he collected over $3i million in contributions.

"There's nothing wrong with religion being big business," Falwell said yesterday. cIt ought to be the biggest business in the world."

Both the students at the rally and politicians who know Falwell said yesterday he has a strong following both in Virginia and the country.

"He has an eormous following. If he endorses you, it has a very high impact," said William A. Royall, special assistant to Virginia Gov. John N. Dalton. Falwell is "political in that he lobbies for what he believes in," Royall said.

That is the flag, Jesus, the Bible, modest dress and "one man for one woman for one lifetime," he said yesterday.

"I believe everything he says," said Louann Latour, 20, a student at Falwell's Liberty Baptist College who attended yesterday's rally. "I feel I can trust him."

Latour said students at the small Lynchburg college are prohibited from drinking, smoking, reading certain books and watching the television programs "Charlie's Angels," "Three's Company" and "Soap." The students are allowed to "double date," she said.

A typical date, said student Wes Beals, 21, included "bowling, or watching a Walt Disney movie. It's exciting. We have a good time."

"I'm here because I love America and want to see a revolution for Christ," said Tina Hoover, 13, a student at the Rosedale Christian Academy in Winchester, Va.

Carrying signs, "The King is Coming: Repent," the students sand religious and patriotic songs. Joe Peet, 22, of of Tom River, N.J., dressed as a Minuteman, said he was "ready to fight" for Christ.

As the rally drew to a close, Carol Elzy, 18, of Hammanton, N.J., walked by the Capitol steps and picked up one of Falwell's "Clean Up Amcerica" questionnaires.

How dirty is America? She was asked.

"It's hard to say," Elzy said with a shrug. "I'm not that well informed." CAPTION: Picture 1, The Rev. Jerry Falwell, right, leads flag salute at Capitol. Others are, from left, Rep. Robert Dornan, and Sens. Gordon Humphrey, John Warner, Paul Laxalt and Jesse Helms. About 8,0000 took part in the rally. By James K. W. Atherton-The Washington Post; Picture 2, The Rev. Jerry Falwell tells rally that he will stamp out "the national cancers degrading to the Republic." By James K. W. Atherton-The Washington Post