Eastern Caribbean neighbors have cast a wary eye on Grenada's revolutionary government and its Soviet and Cuban links but have avoided following the United States into a hard-line boycott of an island that is still one of their own.

The reluctance grows from strong attachment to efforts to increase Caribbean cooperation, seen as essential for prosperity in the region's microstates, and a conviction that most of Washington's concern revolves around U.S.-Soviet strategic competition that has little to do with the islands' own economic problems.

"I am no more enamored of the direction of the new government in Grenada than is the Reagan administration," said Foreign Minister Louis Tull of Barbados, adding later: "We cannot resolve it with the more extreme position that the United States might be disposed to take. I don't expect the government of Grenada to back off. They've gone too far. You have to live with them."

The most concrete expression of regional concern has been last fall's signing of a Regional Defense System pact excluding Grenada. The accord grew from talks begun soon after Prime Minister Maurice Bishop took over the island in a March 13, 1979, coup. It links Barbados, St. Vincent, Dominica, St. Lucia and Antigua, all U.S. friends, in an agreement to share intelligence and promote military cooperation under a coordinating body here commanded by Col. Rudyard Lewis, chief of staff of the Barbados Defense Force.

"It goes back to Grenada doing something none of these countries has ever done, that is, inviting in the Cubans and the Soviets," said a foreign diplomat.

At the same time, the Caribbean nations have rejected efforts by the Reagan administration to encourage political and economic isolation of Grenada. The United States, applying the policy strictly, has excluded Grenada from its Caribbean Basin Initiative and refused to accept a Grenadan ambassador to Washington or allow the regional U.S. ambassador, Milan Bish in Barbados, to visit nearby St. George's.

The regional Caribbean Development Bank turned back intense U.S. pressure in June 1981 to cut Grenada out of a $4 million U.S. grant going through the bank to eastern Caribbean countries for "basic human needs" projects. Then the regional unity organization, Caricom, compromised at its summit conference last November on a human rights declaration that U.S. diplomats had hoped would embarrass Grenada.

Bishop told his colleagues at the Jamaica gathering that Grenada is seeking a new kind of democracy, breaking sharply from parliamentary systems cherished by the region's other islands. He gave what one participant in the meeting called "a solemn undertaking" that the system would lead to genuine democracy and eventual elections.

Tull, reminded that Bishop came to power in the area's first armed coup, was asked in an interview whether in his assessment such a system could lead to peaceful change in leadership. "One is looking forward to that," he smiled.

One reason for the lack of alarm in neighboring islands is that Grenada's revolutionary government has shown little sign of trying to export its ideas to the rest of the English-speaking Caribbean. A diplomat eager to incriminate Bishop's rule said only that some leftists from Dominica had visited the island and that some leftist pamphlets had made their way from Cuba to St. Lucia via Grenada.

"I would say all the countries of the eastern Caribbean are very concerned about security matters, more concerned than they have been in a number of years," said Tull. "But. . .we are more concerned about welfare, about education, about housing." For that reason, Caribbean leaders look with interest on what the United States estimates at $23 million that Grenada received in foreign aid in 1982, making it what one diplomat called "the most lavishly aided island in the region."

An economic analyst monitoring the aid said most of it came from Cuba, East Germany, the Soviet Union, the European Economic Community and Canada, in that order. The annual figure is bloated by aid for an airport under construction. It nevertheless is compared to aid allotted for the area's other countries under the Reagan administration's Caribbean Basin Initiative, which has not got off the ground.

"It does create a feeling of disillusionment among the micro Caribbean states that pinned their faith in U.S. aid when they find they are getting relatively--I want to be fair--relatively less aid than Cuba or Grenada," Tull said.