A former Korean Central Intelligence Agency operative here yesterday described his delivery of $300,000 in cash to a Korean-born Lanham, Md., businessman as part of a plan reportedly approved by Korean President Park Chung Hee to influence members of the U.S. Congress.

Speaking through an interpreter, former KCIA agent Sang Keun Kim said he made the $300,000 delivery - part of a total of $600,000 he said he ultimately turned over to the businessman, hancho Kim, from the Korean government - on Sept. 12, 1974.

S.K. Kim, no relation to the defendent, then produced what he said was a receipt handwritten by Hancho Kim for the Sept. 12, 1974 delivery.

Kim has denied ever receiving the money and has implied through his attorney, David Povich, that the "receipt" is a forgery. Povich has portrayed Kim as the innocent victim of a KCIA plot by S.K. Kim and others to hide KCIA cash in the United States.

S.K. Kim is the only prosecution witnes scheduled t testify about the direct payment of funds to Hancho Kim, and Povich has made it clear that Hancho Kim's defense will be based on claims that S.K. Kim is a trained spy who is lying in this case.

Hancho Kim is the first person to go to trial on criminal charges in connection with the lengthy investigation into alleged Korean influence-buying in Congress. Former U.S. Rep. Richard T. Hanna (D-Calif) pleaded guilty in the probe last week.

The government contends, basically that Hancho Kim was recruited by the KCIA to replace Tongsun Park as the agency's main operative in the influence-buying. Howere, Hancho Kim used the funds for his personal use instead of attempting to bribe members of Congress, the government says.

Hancho Kim is charged with conspiring to defraud the United States of the proper services of members of Congress and lying to a grand jury probing the influence-buying scandal.

much of S.K. Kim's testimony has been made public before in testimony before a congressional committee. Yesterday was his first recounting of it in a courtroom where he is expected to face intense cross-examination.

S.K. Kim said yesterday in late summer of 1974, KCIA supervisor Gen. Yang Doo Wan instructed him to meet with Hancho Kim.

S.K. Kim said he met with Hancho Kim at the latter's Lanham home 'not long after" receiving the letter and there learned of Hancho Kim's participation in the alleged plot to influence members of Congress.

S.K. Kim said Hancho Kim told him that President Park's wife had asked at one point to work for South Korean interests in the United States, but that he had told her he was a businessman who was "not interested in things political" and refused her request.

Howere, S.K. Kim testified, Hancho Kim told him in September 1974 that he had decided to cooperate with the Korean governmentt after President Park's wife was assassinated.

"He said we now have a chance to work together on important things . . . This is an important matter and in order to make sure it succeeds I draw you into my confidence," S.K. Kim said through an interpreter.

S.K. Kim testified that Hancho Kim told him only three people in Seoul - including President Park - know about the project and hat only two of them would know about it in the United States.

Hancho Kim was supposed to attempt to halt what the Korean government saw as a waning U.S. interest in South Korea, and fight against reduction of U.S. aid to the country, S.K. Kim added.

"He [Hancho Kim] said this required a great amount of money and by giving money and gifts to American congressmen the purpose could be achieved," S.K.Kim responded to questioning by Justice Department attorney John Kotelly.

S.K. Kim said Hancho Kim referred to only one congressman - Rep. Tennyson Guyer (R-Ohio) - by name during the conversation, and indicated he would use Guyer to cultivate ties with other members of Congress. The government said it has no evidence that Hancho Kim gave any money to congressmen, and said Guyer and Kim knew each other through a mutual interest in Findlay College in Ohio.