President Kenneth Kaunda took a long step today toward accepting the Rhodesian guerrillas' demand that power be turned over directly to them by the white minority government is Salisbury.

The Zambian leader is regarded as a key moderate among the five frontline states sponsoring the drive against Rhodesian Prime Minister Ian Smith's government. He is on record as formally supporting the recent Anglo-American diplomatic initiative including a key provision aimed at supplanting Smith first by a British caretaker administration and then by a government freely elected from all the country's political groups - including those with no armed forces.

Peacocks strutted on the golf green just outside Kaunda's office in British-built State House as the Zambian president, in an interview, praised the example of Mozambique, where the guerrilla group that won power kept it.

Britain, the United States, the United Nations, the frontline staes and, most important, the people of Rodesia - which it known to the balck nationalists as Zimbabwe - "will have to accept the handing over of power to the Patriotic Front," the guerrillas' umbrella organization, he said.

Just as the Anglo-American initiative that was disclosed Sept. 1 specified that the new army would be "based on the liberation forces," he said, so "let the political structure be based on liberation forces."

Smith would be "less than human" not to be "anxious" about such a turn, he granted. But black Rhodesian politicans without fighting cadres - he named Bishop Abel Muzorewa, the Rev. Ndabaningi Sithole and James Chikerema - "will be just as anxious" and "would believe they would be looked at by the liberation forces as sellouts." "We must consider this," Kaunda said.

One possible "guarantee" would be to preserve the existing Rhodesian police force ("minus some notorious leaders"). Kaunda suggested, and another would be to preserve certain units of the Smith government's army.

Asked about the likelihood of elections, Kaunda said this war for the Patriotic Front to decide. The front's various factions have all resisted the idea of holding elections and thereby putting at risk the power they mean to seize by force.

The Smith government scoffs at the prospect that what it calls "terrorists" - a term that Smith did not use in his secret meeting with Kaunda here Sept. 25 - would sanction an open political process.

"May I be frank with you?" Kaunda went on. "Would anybody seriously believe that Patriotic Front forces, in a country where Britain and all others failed to convince the rebels (Smith) to give up power, where they have made Britain and Smith change their minds - would anyone think they would be happy to serve other leaders? . . .Give them time to settle down. They have been fighting . . .To ask them to move out is to ask for civil war."

It was suggested by others later in the day that Kaunda is under heavy pressure - especially after Robert Mugabe, leader of one wing of the front, sharply criticized him for receiving Smith - to reaffirm his credentials as a supporter of liberation movements.

In the interview, however, even as he bowed to the Patriotic Front, Kaunda invited London and Washington to intensify their diplomacy. There had been "not much progress" on the Anglo-American initiative, he complained. To the key question of how to remove Smith, there had been still "no definite answer."

If Britain and the United States did not move quickly, he said, there would be more bloodshed and "the more bloodhsed, the less the chances of creating a nonracial society" in Zimbabwe.

He conceded differences between two Patriotic Front factions: Mugabe's, which is the most active fighting group and operates chiefly out of Mozambique, and that led by Joshua Nkomo, which operates our of Zambia and is sometimes accused of husbanding its forces for later use against Mugabe's. Their rivalry has given central place to the question of whether they will turn on each other once Smith is beaten, just as the nationalist groups did in Angola.

While reiterating hopes and appeals for front unity, Kaunda held Mozambique up as a favorable example. There a single liberation group took power with discripline and spirit . . .strength," he said.

It is said throughout southern Africa that Kaunda favors Nkomo as the man to unity the front and lead an independent Zimbabwe. Is that true, I asked.

Kaunda called Nkomo a longtime personal friend, but said he could not and would not play kingmaker. In 1974, Kaunda obtained Kaunda's release from Rhodesian detention along with other jailed nationalists.

Mugabe, he said, had stayed "right here" - he pointed to a room over his head - while preparing his recent blast against Kaunda.

The Zambian leader expressed his "love and respect" for President Carter for making clear that the American interest in human rights extends to the victims of racism as well as the victims of communism.

If Carter is not re-elected, he said, "we expect a lot of difficulties. The U.S. would then be not on the side of human rights but of wealth" in southern Africa - where "in the end the revolution will make the French Revolution look like an early morning picnic."

Of the Soviets, who fund and arm the Patriotic Front, Kaunda pointed out that they did so only after the West had refused support. "Americans should see Russian participation as a reaction to their own policies," he said. "I do not need a Communist to tell me when my people are repressed."