Cuba signals it would rather talk than fight with US.

Cuba is sending a new message to Washington these days: We would rather talk than fight. After more than 20 years of bitter confrontation with the United States, there are signs that Cuban President Fidel Castro may be ready to strike some sort of deal with Washington.

If such a shift is under way, Dr. Castro may address it in his annual July 26 speech, commemorating the 32nd anniversary of the start of the Cuban revolution. In the past, he has often used the occasion to announce or suggest significant changes in his thinking and government.

What would prompt Cuba to try to improve relations? Cubanologists answer:

* Cubans expect President Reagan to win reelection, which, in their view, means the US will continue to resist all Cuban efforts to expand its role in the hemisphere.

The choice then is either coexistence with Washington or continued pressure from Washington - with the outside possibility of a US military attack on the island. Cuba wants to prevent this at all costs.

* Cubans would like to share in the economic benefit of ties with the US. While the Soviet Union props up the Cuban economy with large-scale aid and subsidies, there has been relatively little improvement in the island's economic fortunes over the past two decades.

Beset with frustratingly unresolved economic difficulties, Cuban officials reason that a link with Washington, allowing for at least limited Cuba-US trade, might help Cuba lift itself out of those difficulties.

Whether Castro or the Reagan administration is ready to make the compromises necessary for a deal remains to be seen. Cuban officials here indicate Havana might be ready to make some sort of gesture toward limiting some of its support of leftist guerrillas in Central America.

So far, Havana has made no formal overture to Washington.

It is all being done by ''signals.'' But the signals are numerous.

The start of talks between the two nations on the refugee issue, begun in New York earlier this month, is one. The session, which brought Cuban Vice-Minister of Foreign Affairs Ricardo Alarcon Quesada to the US, did not produce immediate results.

But it was the first high-level meeting between Cuba and the US during the Reagan administration.

Cuba, moreover, indicated a new willingness to take back some of the 1,000 criminals who joined the 1980 Mariel boat lift to the US. The issue has been a bone of contention between Washington and Havana ever since. (And Cuba may still have some qualifications about taking back some of the ''Marielitos.'')

In addition, here in Cuba, the public anti-US rhetoric of the past decade has been stilled. There are now relatively few strident attacks on capitalism, the US, and US officials in the Cuban press or over Cuban television.

During the visit of the Rev. Jesse Jackson at the end of June, such attacks virtually disappeared from the Cuban news media - and they have yet to reappear in any degree of intensity.

All this suggests to many diplomatic observers here that Cuba is indeed interested in improving relations with Washington.

But US officials are at best skeptical. They doubt that Cuba is prepared to make the compromises that Washington demands for improved relations. These include a reduction in the role of the Soviet Union in Cuban affairs.

US sources also say that private talks between middle-level Cuban and US diplomats last year fell through because Cuba could not decide just what it was prepared to offer in a rapprochement with Washington.

The US sources also point out that the Cuban signals are mixed. There is no indication that Castro has any intention of lessening his ties with the Soviet Union or of giving up some of his revolutionary goals.

Still, Cuba watchers here are convinced the Castro government has made a calculated decision to push for at least a limited rapprochement with the Reagan administration.

''Castro seems to have decided that if you can't lick 'em, you join 'em,'' commented a Western diplomat in discussing the changing tone of Cuban attitudes about its relationship with the US.

All this comes as the Castro government pulls out all stops today to celebrate the revolution's anniversary. Not only will Castro give his state-of-the-nation-type address, but there are also dozens of official delegations from around the world in attendance. It is a big show.

In his remarks, Castro is certain to focus on the quarter century that he has been in power. It was 25 years ago, on Jan. 1, 1959, that he and his small band of revolutionaries emerged from the eastern mountains of Cuba to take control of the island from dictator Fulgencio Batista.

The quarter century has produced remarkable changes in Cuba. Early in the revolution Castro embraced Marxism and turned his island, the largest in the Caribbean, into an ally of the Soviet Union. He brought advances in education, health services, and housing to his country during the early years. But as the years went on, he increasingly tied Cuba's fortunes to the Soviet Union.

The result was not only a break in relations with the US, but also several serious confrontations with Washington.

Meanwhile, more than a million Cubans fled the island in a series of waves during the 1960s and 1970s, the latest being the 1980 Mariel boat lift which brought more than 125,000 Cubans to the US.

There are hundreds of thousands more who would like to follow.

Cuban officials quietly say they hope the US will open its doors to perhaps 400,000 Cubans who had signed up for the boat lift before it was abruptly closed down by Castro.