Yugoslavia is planning a major political trial of about 50 persons allegedly involved in a campaign to link Kosovo Province with Albania.

First public mention of the trial, which is to begin in two weeks, came yesterday in the influential Belgrade newspaper Politika following months of rumors of nationalist unrest in Kosovo, which is largely populated by Albanians.

The disturbances caused President Tito to pay a hastily arranged visit to Kosovo last October -- one of his last appearances before the illness that now has the president near death.

The timing of the trial, the most important of its kind for several years, appears to reflect official determination not to allow an upsurge of divisive national feelings after Tito dies. While the transition to the post-Tito era appears to be proceeding smoothly, Yugoslav leaders are aware that their country's unity could be threatened in the years ahead not merely from the Soviet Union, but also as a result of internal differences.

Kosovo, which borders on Albania, has a large Albanian population. It is underdeveloped and has long been regarded as one of the weakest links in the multinational Yugoslav federation. The province was shaken by violent riots in 1968 and four years ago 31 members of an Albanian National Liberation Front were sentenced to prison terms of up to 15 years.

Politika said around 50 Albanians, including 19 past convicted nationalists, are now charged with organizing "anti-state activity" throughout the region. It said they had distributed antigovernment pamphlets, spread false rumors about Yugoslavia, and advocated "irredentist views," that is, they called for Kosovo to be separated from Yugoslavia and united with Albania.

Tito, during his visit to Kosovo, sharply attacked what he called new attempts to undermine "brotherhood and unity" in the region and sow discord between Albanians and Serbs. Huge crowds were mobilized in a demonstration of mass public support to greet him, but informed sources sid antigovernment demonstrations continued after his departure.

Over the last decade, Yugoslav leaders have successfully defused demands by some Albanian extremists for unity with Albania by pouring development funds into Kosovo and granting it a large measure of political autonomy. But despite huge investments, the province is still way behind the rest of Yugoslavia and has been particularly affected by a new economic crisis.

Complicating the problem is the attitude of the isolationist Albanian regime across the border. Albanian leader Enver Hoxha, a self-proclaimed admirer of the late Soviet dictator Josef Stalin, has frequently accused "the Titoist clique" of deviating from Marxist ideology and of discriminating against Yugoslavia's 1.5 million Albanian minority.

Haunting Tito's likely successors is the possibility that the Kremlin might somehow regain its influence over Albania -- and use the country as a base for exercising pressure against Yugoslavia. Politika said those accused include former Cominformists, or Soviet sympathizers who sided with Stalin in 1948 when Yugoslavia was expelled from teh Soviet-dominated world communist movement.

As long as Hoxha, 72, is alive, there seems little possibility of his strategically placed country being attracted back into the Soviet Bloc. He jettisoned "our eternal alliance" with China two years ago but has since rebuffed all Soviet offers of better relations.

Yugoslav officials are aware that like Tito, Hoxha is nearing the end of his political career -- and alliances in the Balkans could change after his death. But they have been encouraged by more friendly noises from Albania during Tito's illness, and in particular a remarkable statement pledging Albanian support for Yugoslavia in the event of a Soviet attack.

Politika reported that strict security measures would be in force at the forthcoming trial to avoid what it described as "an attempt by somebody from among the masses attempting to settle acocunts with the accused." Most such political trials are in any case held behind closed doors.