A senior Soviet Communist Party official arrived here today on a surprise visit that appeared to reflect the Kremlin's concern at signs of renewed instability in Poland.

Shortly after his arrival, Konstantin Rusakov, a secretary of the Soviet party's Central Committee, met with Poland's military ruler, Gen. Wojciech Jaruzelski. Polish analysts believe that the main purpose of his visit, which evidently was arranged at short notice, is to gather firsthand information about the political situation here following a spate of symbolic strikes and protest demonstrations earlier this month.

Rusakov, a former aide to President Leonid Brezhnev, is responsible for the Soviet party's relations with other ruling Communist parties. He is the most senior Soviet party official to visit Poland since imposition of martial law last December.

Rusakov's visit comes at a crucial time as the Polish leadership must soon decide whether to move toward an agreement with the suspended Solidarity trade union or attempt to crush it completely. The government has been following a policy of carefully calibrated suppression combined with stabs at economic reform.

The rioting, which broke out in more than a dozen Polish cities simultaneously, was a reminder of how quickly the Polish crisis can change. People who had thought before the protests that Jaruzelski had time on his side now think it seems to be running against him.

So far, the authorities have managed to contain the disturbances through a huge deployment of riot police on the streets and security agents inside the factories.

Moscow could see these protests as indicating that Poland's crisis, with its debilitating effects for the rest of Eastern Europe, is far from over. But at present the Kremlin, like the Polish leadership, has shown no clear idea of what to do next, beyond blaming "imperialist subversion."

Despite reports of divisions within the Polish Communist Party, there is no evidence that the Kremlin is preparing to drop Jaruzelski in favor of a hard-line ideologue. While Soviet leaders may have reservations about Jaruzelski's relatively conciliatory policies, they regard him as "their man" and appear anxious to bolster his authority.

Jaruzelski is due to complete a tour of Soviet Bloc capitals later this week when he leads a Polish delegation to Bulgaria. The pattern of the tour was set by a visit to Moscow in early March, when he was accorded a hero's welcome and expressions of gratitude from the Soviet leadership.

Moscow's renewed concern at developments in Poland is seen in recent commentaries in the official Soviet news media. An article in today's Communist Party daily Pravda accused the United States of "outright interference in internal Polish affairs" and blamed in particular Radio Free Europe.

"Facts show that the aggressive circles of the imperialist states, above all the United States, are conducting a subversive policy against the socialist countries," Pravda charged. "The subversive actions conducted in the framework of this policy . . . are assuming ever more acute forms."

Pravda said that "the psychological warfare" waged by Washington was "without precedent in peacetime."

The attacks on the United States appeared to disguise the internal policy dilemma now facing the Polish leadership and, by extension, the Kremlin. The consensus among most analysts here is that the present political stalemate cannot last and that the most probable short-term solution is greater repression.