President Amin Gemayel, in an emotional 30-minute address on national television tonight, strongly appealed to the Lebanese to put an end to the country's violent civil strife. He warned that if they failed to do so quickly Lebanon might remain indefinitely "under the yoke of occupation."

The 41-year-old president appeared tired and drawn during the 30-minute speech, clearly showing strain from the recent bombings of Beirut and the nonstop negotiations to deal with the myriad problems facing this country.

Gemayel signaled an intention to send the Lebanese Army into the strife-torn Chouf Mountains, south of Beirut without first meeting the demands of Druze militiamen. This seemed to indicate that the flurry of recent efforts by U.S. diplomats and emissaries of moderate Arab states to mediate in the affair had failed.

The United States has persuaded Israel to delay for a few days its withdrawal from the Chouf Mountains, but Reagan administration officials said no decisions have been made about moving the multinational force into that area after the Israelis leave. Details on Page A27.

Druze leader Walid Jumblatt repeatedly has threatened to wage all-out war against the Army if Gemayel did not make concessions to the Druze. Earlier this month, to demonstrate the seriousness of the warnings, Jumblatt's militia attacked an Army outpost, kidnaped and briefly held three Cabinet ministers and shelled the capital several times, with some of the rounds falling near the presidential palace.

In a rare admission from a Lebanese, Gemayel said the problems here go beyond the occupying Syrian, Israeli and Palestinian forces.

"Dear Lebanese, it has been said to you that partition is about to take place," he said, pointing a finger at the audience. "In reality, Lebanon is living divided in itself. The time has come for us to work together."

Unless that is done, he said, "the foreigner will crowd us out of our land and use it for himself and the citizen will find himself under the yoke of occupation."

Gemayel sought to allay Moslem fears that he intended to use the Army and the powers of government to give his fellow Christian Phalangists dominance in a country where none of the warring religious sects is a majority.

The national appeal was clearly designed to win Moslem acceptance for deploying the Lebanese Army in the bloody mountains overlooking Beirut when Israeli forces pull back to positions in southern Lebanon.

Announcement of the planned Israeli departure has been the trigger for a sharp escalation of the months of civil warfare between Christian Phalangists and Moslem Druze militiamen. The Druze, expressing the fear that the Army would side with the Phalangists against them, have shelled Beirut and shut down the airport to press their demand for a new political agreement before the Army is deployed.

Gemayel made no mention of the Druze demands tonight. But he repeatedly called on all sides to accept the Army, saying it was going to the mountains to protect people regardless of their religion.

Gemayel spoke of giving "consideration" to changes in Lebanon's political system, which gives Maronite Catholics the presidency and more positions than any sect in the government and parliament. But he indicated that any revisions would come later.

He and his advisers have strongly resisted making changes now, expressing the feeling that to do so would be to succumb to the blackmail of powerful militias operating in the country. They have indicated that changes should come only after foreign occupying forces leave and the Army has extended its authority over the entire country.

Jumblatt has demanded that the Druze, a secretive, breakaway Moslem sect, be given a greater share of power in the political arrangement and that the changes be made before the Army is sent to the Chouf.

"I know and you know that what has been done to Lebanon in eight years of war cannot be undone with a magic wand," Gemayel said. But "the danger that looms is immense and the effort required of us is huge and the time we still have is narrow unless we begin from now to anticipate events and difficulties."

Washington, strongly concerned that Gemayel had been relying too heavily on the advice of longtime Christian Phalangist friends, has been placing strong pressure on him to reach out to the Moslems.

Gemayel's appeal came amid other faint signs of progress in the effort to avoid more warfare.

Pierre Gemayel, the president's father and the leader of the Phalange Party, said today that Christian militiamen in the hills were willing to leave the mountains to allow the Army to go in.

There were indications that the elder Gemayel was acting to rein in Phalangist militiamen who recently have been appearing armed in Moslem areas of the capital, prompting some Moslem militias that were disbanded last fall to rearm.

Meanwhile, earlier, Druze leader Walid Jumblatt warned that full-scale fighting for control of his mountain stronghold was ahead, United Press International reported.

[The battle of the ]Chouf[ mountains is approaching, and the fate of Lebanon depends on it," Jumblatt said in an interview published by the official Syrian newspaper, Al Baath, and quoted in a broadcast by state-run Damascus radio.]