WARSAW, SEPT. 25 -- A year-long warming trend in Polish-U.S. relations has nearly restored formal ties disrupted after Warsaw's suppression of the Solidarity movement, but the United States seems far from returning to its former role as a major economic partner for this Eastern Bloc country, Polish officials and diplomats say.

When Vice President Bush arrives here Saturday for the highest-level U.S. visit in eight years, the government of Gen. Wojciech Jaruzelski will in some ways have accomplished a key task in its long struggle to "normalize" Poland. In a slow but steady process, communist authorities have managed to rebuild ties with the Reagan administration without allowing the resurgence of the free trade unions that rocked the country in 1980-81.

Tough economic sanctions imposed by the United States after Jaruzelski declared martial law in 1981 were finally lifted in February, six months after an amnesty freed most political prisoners. Officials in both Washington and Warsaw confirmed this week that an exchange of ambassadors will soon be carried out, ending a hiatus of nearly five years in full diplomatic representation.

Yet if the semblance of cooperation has been restored in this once thriving East-West relationship, Polish officials have noted with increasing bitterness that more substantive improvements have been slight. Desperate for inflows of fresh western capital and technology to overcome a prolonged economic crisis and eager to create a distinct diplomatic identity for Poland among Eastern Bloc states, Warsaw has been largely frustrated in its hopes that normalization with the United States would open the way to these gains.

Instead, many Polish and American analysts believe the position Poland held among Eastern Bloc states during the 1970s as an economic and political partner of the United States is not likely to be regained in the near future.

"Real effects have yet to be seen" in the improvement of relations, said Polish Foreign Minister Marian Orzechowski in a recent interview published in the state-run press. He added bitterly: "The United States has not shed at all -- or has been shedding very reluctantly -- its stereotype of Poland as a country that is allegedly not sovereign, lacks stability and is weak. The Americans believe many myths."

The relatively weak U.S. position here strongly colors an overall relationship with Eastern Europe that has been largely unaffected so far by the improvement in atmosphere between Washington and Moscow.

The Reagan administration has good and improving relations with Hungary, the bloc's most open and liberal country. However, ties with conservative states such as Czechoslovakia and East Germany remain limited and a once warm association with Romania is deteriorating.

Many U.S. policymakers agree that Poland, with its keen interest in western trade and traditionally pro-American society, is in many ways a natural focal point of East European policy. But they say that the continuing repression of Solidarity makes tension with Jaruzelski's government inevitable, while the economic disorder and staggering $31 billion foreign debt ward off even generous-minded investors.

Despite the outward improvement of relations with Jaruzelski's government, the Reagan administration has maintained strong links with the surviving, semiclandestine ranks of Solidarity. Bush is due to meet with leader Lech Walesa here, and the White House recently approved a congressional request to appropriate $1 million for the banned union.

The unusual funding move in July provoked angry protests from Polish authorities and seemed to embarrass some Solidarity leaders, who were loudly denounced by government spokesmen as "paid agents of Washington." Walesa eventually announced that the money would be used for a special social welfare fund rather than organizing or underground printing activity.

For its part, Jaruzelski's government has kept up a steady stream of hostile propaganda against the Reagan administration. The official Communist Party newspaper Trybuna Ludu, for example, prepared for Bush's visit yesterday with an extensive article on alleged human rights violations in the United States, charging that there are "tens of thousands" of American political prisoners.

While the political conflicts were perhaps predictable, Polish authorities have appeared disappointed in the slow rebuilding of U.S.-Polish economic ties. U.S. figures show that bilateral trade increased 36 percent in the first seven months of this year compared to 1986 as U.S. sanctions that limited Polish exports were removed.

However, total Polish-American trade is still less than one-third of its peak level of 1979-80, and neither the Reagan administration nor U.S. banks have yet been willing to extend new loans to Poland. Moreover, Polish authorities contend that the Reagan administration has contributed to Poland's inability to win crucial new economic agreements with the International Monetary Fund and the Paris club of western government creditors.

"A formal lifting of restrictions and sanctions does not mean their real lifting. In a hidden way, they are working as before," charged Orzechowski in his recent interview. "Financial arrangements or credit are virtually nonexistent between the two countries."

U.S. officials concede that progress in economic ties has been slow, but argue that the fault lies with Polish authorities' failure to restore order to the economy seven years after its collapse.