Rosalynn Carter encountered the first sign of hostility in her Latin American tour today as student demonstrators shouted "Rosalynn Carter, go home!" and "Bloody Rosalynn."

About 200 demonstrators threw stones, bricks, boards, auto tires and clods of dirt at military police and press outside the Legislative Palace as the President's wife conferred inside with members of this country's Supreme Electoral Tribunal.

The demonstrators stood on top of a wall surrounding a medical college across the street from the palace.

Police retaliated against the demonstrators with tear gas.

Ecuadoran sources said that some of the same demonstrators have conducted other antigovernment protests. The most recent of these, earlier this week, was on behalf of the National Teachers' Union, which has been on strike since mid-May for better pay and working conditions.

But today's demonstration appeared directed only at Mrs. Carter.

More typical of her Ecuadoran reception, however, was a sign saying "Bienvenida (Welcome) Rosalynn Carter" that greeted her from the top of a building she visited later in the day.

Sounds of bursting tear-gas cannisters could be heard inside the paneled, flag-draped chamber of the Tribunal, which is overseeing the process of changing this country's government from a military junta to a constitutional democracy.

As she emerged from the Legislative Palace, Mrs. Carter was asked if she had heard the soldiers dispersing the demonstrators.

"I heard some noise, but I didn't know what it was," she said. Asked what she thought of the demonstration, she said, "I don't know anything about it."

By Ecuadoran standards, the demonstration was small. Nor did it compare with the 1958 demonstration against then-Vice President Nixon, whose life was endangered when demonstrators stoned him and Mrs. Nixon in Caracas, Venezuela.

After her meeting with the Tribunal, Mrs. Carter went to a center for working boys at the Plaza San Martin, a five-minute drive from the Legislative Palace. On top of the center was an enormous red sign saying "Bienvenida [Welcome] Rosalynn Carter."

She is on a two-week, seven-nation tour of Latin America as the personal envoy of her husband and visited Jamaica and Costa Rica before coming here.

Just before Mrs. Carter arrived at the Legislative Palace, the demonstrators, who called themselves "Revolutionary Democratic Students," began shouting in Spanish such slogans as "Rosalynn Carter, you have nothing to do here," "Yankees want to reinforce their imperialism" and "Yankees exploit the people, the workers, the farmers."

They rained missiles down onto the Avenida de Colombia before Mrs. Carter arrived at the palace: As reporters and photographers watched from across the street, the demonstrators began shouting and throwing stones and brick.A brick hit me on the ankle and others hit Nancy Lewis of the Cox newspapers and Hermes Munoz, an NBC cameraman. None of us was injured.

It took two rounds of about 20 tear gas cannisters to disperse the demonstrators, two tossed two Molotov cocktails at the military policy.

Acrid smoke filled the area, but Mrs. Carter appeared not to notice it as she left the palace, she did not see the demonstrators because she entered and left the building from an entrance on a side street.

Mary Hoyt, Mrs. Carter's press secretary, said the White House party had expected some demonstrators at Quito's airport when Mrs. Carter arrived Wednesday. But there was no demonstration, and the First Lady received an elaborate Welcome.

Earlier, Mrs. Carter held a news conference after meeting for three hours with the three leaders of the military junta.

She said she discussed the proposed Israeli sale of Kfir fighter planes to Ecuador, which President Carter vetoed in February. The United States has veto power over such sales because the plane is equipped with an American engine.

Mrs. Carter said she explained to Alfredo Poveda, president of the military ruling council, that President Carter's decision was not directed only at Ecuador.

She said it was part of "a global policy on armaments," in which the United States intends to decrease the sale of armaments every year.