A South Korean government plan to imprison its most vocal political opponent on his return from the United States next month may cast a pall over an expected meeting of President Reagan and South Korean President Chun Doo Hwan, State Department officials said yesterday.

Opposition leader Kim Dae Jung, who has been living in the United States since being released from prison and exiled from Korea in December 1982, has announced that he will return Feb. 8 to work for a "restoration of democracy." Kim said yesterday that his chief of staff in Seoul has been informed by two officials of Chun's "Blue House" that he will be jailed on his return.

A working visit by Chun in March is expected to be announced shortly by the White House.

The State Department sources expressed concern that a renewed public uproar over Kim could dominate the visit and thus diminish its value to the two governments.

Chun's previous trip to the White House in February 1981 was preceded by a period of jockeying between Seoul and Washington about the fate of Kim, who then was under a sentence of death. As part of a deal with the incoming Reagan administration, Chun commuted Kim's death sentence 10 days before visiting Reagan.

Publicly, the State Department said yesterday through its spokesman, Bernard Kalb, that the administration hopes the return of the opposition leader to Seoul will be "trouble-free," despite new statements in Seoul that Kim will be jailed on arrival.

Kalb did not take an explicit stand on returning Kim to prison but other sources said the United States has made clear that it takes a dim view of such a move.

Kim is to be accompanied to Korea early next month by Rep. Edward F. Feighan (D-Ohio), former assistant secretary of state for human rights Patt Derian, former U.S. ambassador to El Salvador Robert White and other prominent figures from the United States.

Kim said in a telephone interview that "there is no change in my plan" to return Feb. 8, despite the statement of Choi Chang Yoon, an aide to Chun, that the opposition leader will be imprisoned if he returns. Choi was quoted in a New York Times interview as saying the Chun government "cannot treat Kim as a politician -- he is a revolutionary."

Last Nov. 29, Sen. Edward M. Kennedy (D-Mass.) released a letter from South Korean Ambassador Byong Hion Lew saying that Kim "is required by law to serve the remainder" of a 20-year prison sentence for sedition.

Before being sent abroad Kim served 2 1/2 years of the 20-year sentence, commuted from the original death sentence, in a case widely viewed as a political prosecution.

Kim said he continues to request "a dialogue" and "a peaceful solution" with Chun. Kim said he is "honored" to be called a revolutionary because of his respect for the U.S. founding fathers given that term by the British when they broke away from colonial rule.

Kim's return is scheduled to come only four days before national legislative elections in South Korea. This timing is disquieting to the Chun government and has raised eyebrows among U.S. diplomats concerned about political stability in Seoul.

The opposition leader said he had been willing to return home after the elections if the government, in return, would permit him to accept invitations to visit Austria, France, West Germany, Italy and Sweden on his way back to Seoul. He said that, after extensive negotiations, the government refused his request and precipitated his early-February return.

Despite the tough declarations from Seoul, State Department sources expressed the hope that the Chun government and its best known political opponent are still at a stage of bargaining and posturing, with an accommodation still possible before Kim's scheduled return.

Kim said he plans to leave Washington Feb. 6 and stop briefly in Japan before arriving in Seoul Feb. 8.