Hancho Kim, a Korean-born cosmetics merchant who lives in Lanham, Md., yesterday was convicted by a federal jury of accepting $600,000 in Korean Central Intelligence Agency money to influence members of Congress and then lying about it to a federal grand jury probing the Korean influence-buying scandal.

The government did not allege during Kim's four-week trial before U.S. District Court Judge Thomas A. Flannery that Kim actually paid any money to members of Congress. Instead, the prosecution implied that Kim used the money to go on a spending spree that included his purchase of a new Cadillac, home improvements and payments of his children's private school bills.

The jury deliberated about seven hours before returning the guilty verdicts on the two counts. Kim will remain free on bond at least until his sentencing, scheduled for May 19, but must surrender his passport in the meantime.

Kim, who claimed through his attorney that he never received the money and is the victim of a frame-up by the KCIA, is the first person to be convicted by a jury in the influence-buying scandal. Former Rep Richard T. Hanna (D-Calif.) pleaded guilty last month to receiving $200.000 from Korean business man Tongsun Park.

Kim's trial focused on the credibility of former KCIA agent Kim Sang Keun, who defected to the United States from the Korean embassy in Washington in November 1976, as the influence-buying scheme unfolded. Kim Sang Keun testified during the trial that he had delivered huge amounts of cash from Korea to the Lanham home of Hancho Kim on at least two occasions for the purpose of influencing members of Congress and that he used a Telex machine in Kim's Lanham home to wire messages to the KCIA.

Kim's attorney, David Povich, portrayed Kim Sang Keun as a trained spy and a liar who fabricated his stories and forged documents - including an alleged receipt from Hancho Kim for $300,000 - in a successful attempt to work out a deal so he could stay in the United States.

Povich claimed that Kim Sang Keun was part of a scheme perpetrated by another KCIA official, Gen. Yang Doo Wan, to stash money in the United States so both of them could defect.

Hancho Kim, Povich said was a successful businessman who had large sums of money on his own in Korea and the United States with which to make the purchases described by the government.

Justice Department attorney John Kotelly presented 65 witnesses, most of whom collaborated aspects of Kim Sang Klun's story and the government's allegation that Hancho Kim the first alleged $300,000 delivery on was in dire financial trouble before Sept. 12, 1974, from Kim Sang Keun. The spending spree, according to government witnesses, began almost immediately.

Although the money was allegedly supposed to be used by Hancho Kim only congressman with whom he was to influence members of Congress, the shown to the friendly was Tennyson Guyer (R.-Ohio).

Guyer testified that he received nothing of value from Hancho Kim, and that they knew each other through their mutual interest in Finding College. Kim first came to the United States in 1954.

Guyer did have an article that Kim helped prepare inserted into the Congressional Record, and recommended to another congressman that a similar article be inserted. Guyer said, and the government did not disagree, that the article was inserted solely out of friendship to Kim and their mutual interests in Korean problems.