Just four months after challenging the Kremlin by welcoming Chinese Communist Party Chairman Hua Kuo-feng, President Tito signaled today that he may be ready to meet with President Leonid Brezhnev and smooth relations between Belgrade and Moscow.

Tito met today with Mikhail Solomintsev, an alternate member of the Soviet Politburo. Both spoke warmly of improving relations and there were suggestions that a summit meeting with Brezhnev was being planned.

Planning for a summit meeting between President Tito and Brezhnev was postponed last fall following severe Soviet press criticism of the warm welcome given by Yugoslavia to Hua. In a speech last September, Tito expressed surprise at the Kremlin attacks and forcefully defended his action in assisting China's historic opening up to the outside world.

Solomintsev's visit coincides with other signs that Tito is making another of the swings toward or away from the Soviet sphere that have marked his postwar control of Yugoslavia.

Tito's moves toward closer ties with Moscow have usually been accompanied by a crackdown on international dissent, and the Yugoslav president has called for a reining in of dissidents, accusing them of coalescing against his control.

The mending of fences with Moscow is not necessarily directly connected with the new harsher climate toward domestic political dissent which has become evident over the last week, but both events relrect the skillful political balancing act Tito has performed since he came to power in Yugoslavia after World War II.

After several years of relative relaxation at home and rapidly improving relations with the United States and China at the expense of the Soviet Union, Tito has apparently judged that it is time to nudge the political pendulum in the opposite direction. At the same time, he appears confident that Chinese and American support ahs strengthened his hand for dealing with the Kremlin, without compromising his independent brand of communism.

The Yugoslay leader used the opportunity of celebrations marking the country's Army Day last week to call for stricter measures against dissidents and the unmasking of other, as yet unidentified, political opponents.

He appears to have been particularly alarmed at contacts among Yugoslavia's scattered and ideologically very diverse band of dissidents-including the officialy disgraced former vice-president, Milovan Djilas, the writer, Mihajlo Mihajlov, and nationalists from the Yugoslav republic of Croatia.

Last July, Djilas, who now advocates a more liberal system of government for Yugoslavia, traveled to Zagreb, the Croatian capital, for a meeting with prominent Croatian nationalists. In an interview yesterday, he said the talks had shown that they held certain views in common, but denied official allegations that the meeting was aimed at working out a joint prolitical program.

Djilas, one of Tito's closest wartime aides, said that he and the Croatian nationalists had agreed that the Soviet Union might try to exploit internal political upheavals in Yugoslavia after Tito's death. He added that they had agreed to keep in contact, rather than working in insolation as they had done in the past.

Apparently referring to these contacts in his Army Day speech, Tito said that until now the Governemtn had behaved fairly tolerantly towards dissidents.He added: "We cannot tolderate it any more, we must take measures which according to out constitution and our laws we have a right to do . . Otherwise it would be interpreted as a sign of weakness. We are afraid of no one and nothing."

Asked what he thought Tito meant by these remarks, Djilas, who has been in and out of prison since his dramatic purge in 1954, said they might herald new arrests of political opponents. Describing the chances of his own re-arrest as (possible, but not likely," he said he thought the authorities were more likely to act against Mihajlov, who is visiting in Washington and is due to return here from a six-month tour abroad later this month.

Last week, a Yugoslav newspaper carried a long and clearly officially sanctioned attack on Mihajlov, accusing him of leaving behind "a dirty trail of deceits" during his travels in the United States, Britain, France, and Italy. Claiming that he had extensive contacts with terrorist organizations abroad, it said that an extremist Serbian nationalist group in the United States had contributed to financing his lectures and banquets there.

The Yugoslav authorities face a considerable dilemma in deciding how to deal with Mihajlov, who was released from prison under an amnesty in November 1977 after serving half of a seven-year sentence. Unlike other dissident.s, he enjoys hardly any support within the country itself. It is widely acknowledged that sending him to prison merely gives him an importance and political platform he would not otherwise have acquired.

On the other hand, only last week a doctor in the Yugoslav republic of Bosnia was sentenced to six years' imprisonment for making what were considered "anti-Yugoslav" remarks in a lesser "crime" than those now being alleged against Mihajlov.

Whether by design or coincidence, Mihajlov's spells in prison have tended to coincide with Yogoslav-Soviet honeymoon periods. Russian by parentage, he received his first prison sentence in April 1965 following a sharp Soviet protest over criticisms he made of the Soviet Union in his book "Moscow Summer."

Tito and Solomintsev met on the Yugoslav leader's private island of Brioni in the Adriatic. Colomintsev was officially reported to have conveyed a message from Brezhnev expressing hopes for improved relations, a sentiment echoed by Tito.

An official Yugoslav commentary on the talks stressed the importance of personal meetings between the two leaders, a phrase which has strengthened speculation that Tito may now be ready to go ahead with his plans to meet Brezhnev. They last met in August 1977, when Tito stopped over in Moscow on his way to Peking.