President Carter, beginning a 14,500-mile journey meant to symbolize American ties to the Third World, told Venezuelans here yesterday in their native Spanish that "just as our continents are linked, our destinies are linked as democratic nations."

In hot and hazy weather, Carter was greeted at Simon Bolivar international airport by Venezuelan President Carlos Andres Perez, who seized the opportunity to dramatize Latin America's desire for approval of the Panama Canal treaties.

"You come to Latin America at a time when all of our peoples are directing their eyes and their ears toward the Congress of the United States, toward this great debate which the Senate has at present which will decide the fate of the relations between South America and North America," Perez said.

"Each word pronounced here is of enormous importance, and it will have a very deep impact on Latin America."

It was clear from Perez' remarks that Carter was spared an enormous embrassment two weeks ago when the Senate approved the first of the two canal treaties. But the Venezuelan president also made it clear that Latin Americans remain deeply concerned about the fate of the second treaty, due for a Senate vote in April, and the possibility that the Senate will alter the treaty significantly.

"I understand what has been said here," President Carter replied. "The ratification of the Panama treaties are also important for the United States."

The president's stop here was the first in a week-long trip to four developing nations of South America and Africa. Carter will fly today to Brazil, and later this week to Nigeria and Liberia.

The journey is part of the trip the president orginaly scheduled last fall and which he later postponed and broke into two segments.

Venezuela is considered South America's strongest democracy, a country on human rights and gnerally supported the administration policies.

But Venezuela is also a member of the Organization of Petroleum Exporting Countries (OPEC), where there is growing concern about the decline in the value of enormous quantities of oil, chiefly from Saudi Arabia, Nigeria and Venezuela because of the fall of the dollar.

As if to symbolize the importance of oil and energy to both the United states and the OPEC countries, as Carter and Perez met at Perez's residence, a power outage blocked out large portions of the city for almost three hours.

In Carter's first two public appearances here, the president read prepared remarks in Spanish, a language he mastered several years ago as part of his relentless self-improvement program.

At the airport, Carter sought to tie U.S. interests to those of the Third World and to those of the Third rights message - a message more easily delivered here than it will be to the military government of Brazil.

"We know that what in the modern world affects one nation eventually will affect all of us," he said. "That is why strength of your democratic institutions here means so much to us.

"We know that whenever the rights of any individual in the world are diminished, our rights are in danger, and that wherever they are defended, as in Venezuela, our rights are strengthened," he added.

Perez reiterated his concern about the canal treaties during a 90-minute meeting with Carter, later telling a news conference that he hopes the Senate will reconsider the amendments it added to the first treaty during the debate over the second treaty. Perez noted that he is in frequent contact with Panamanian leader Gen. Omar Torrijos, suggesting that he was actually relaying Torrijos' wishes to Carter.

A U.S. official, however, said Carter believes there is virtually no chance the Senate will reconsider the provisions it added to the first treaty.

Zbigniew Brzezinski, the President's national security affairs adviser, said the canal treaties were themost important that the presidents discussed, with Perez calling them "a watershed" in U.S. relations with Latin America.

Brzezinski said Carter and Perez also discussed nuclear nonproliferation, the Middle East peace negotiations, African issues, including the presence of Cuban troops in the Horn of Africa, human rights and the arms race.

Brzezinski said the United States will shortly circulate a revised version of the five-power proposal for self-rule in Namibia. He would provide no details.

The NSC adviser described the two presidents as being in basic agreement on most of the issues, calling the discussion, "a meeting between two friends."

He said part of the time Carter talked to Perez in Spanish.

Carter, in his earlier public statement told Perez:

"Your country has many times shouldered the burden of reducing regional and international tensions, and of attempting to reduce proliferation of conventional and nuclear arms."

Perez told Carter that "your name has achieved today great dimensions in Latin America and in the world because you have given an ethical meaning to the policies of your government" through the president's stand on human rights.

After Carter reviewed an honor guard of Venezuelan Marines at the airport, the two presidents climbed into a black limousine for more than a 30-minute drive into the city. There were no crowds along the route, which climbs steely up to the city, although people could be seen pearing down the road from the wood-and-brick shanties that dot the hills around Caracas.

The crowds were thicker in the city, but there was little evidence that the government sought to greet Carter with a large shoow of popular support.