Coretta Scott King told a federal jury yesterday in the fraud, theft and perjury trial of former UDC president Robert L. Green that she knows him as a "totally honest, very decent person who is dependable . . . truthful, hard-working and caring."

Testifying as a character witness, King told the jury she has known Green since 1965, when he joined the staff of the Southern Christian Leadership Conference, which her husband then headed, but said she knew nothing of the evidence against him in the case.

King, widow of the Rev. Martin Luther King Jr., was on the stand for less than 15 minutes as the defense began its case after more than three days of testimony by government witnesses.

Green, now an administrator at Cuyahoga Community College in Cleveland, is expected to take the stand in his own behalf today. His wife, Lettie Green, also is scheduled to testify today. The case is expected to go to the jury tomorrow.

The charges against Green focus on a $1,399 Sansui stereo system and a $1,994 Hitachi projection television that were bought in 1983, shortly after he became president of the University of the District of Columbia.

In presenting the government's case, Assistant U.S. Attorney Daniel J. Bernstein said that the two items were paid for with District funds, money from special accounts controlled by Mayor Marion Barry's office, and that Green took the equipment illegally when he was forced out as university president in 1985.

Dwight S. Cropp, Barry's director of intergovernmental relations who formerly served as secretary of the District and as an assistant to Green at UDC, was the prosecution's key witness, testifying that he gave Green $1,400 in cash to pay for the stereo and to arrange for the purchase of the television.

Cropp, who at the time controlled five mayoral discretionary funds, said Green wanted the transactions kept secret to avoid controversy with the university's board and the board of the UDC Fund, which had turned down Green's request to buy the stereo for Green's university residence at 3520 Rittenhouse St. NW because it would not directly benefit students, the fund's main purpose.

According to testimony by Cropp and two university officials, acting Associate Vice President Edward Holland and Director of Development Ann O. Hughes, the UDC Fund extended a $1,399 loan to Green on Sept. 16, 1983, to buy the stereo system.

Hughes said she had arranged for Green to repay the loan by contributing honoraria he would earn to a special account in the fund. But about three weeks later, Cropp and Holland testified, Green became upset that the loan had become known to others and wrote out a personal check to reimburse the UDC Fund.

Holland testified that Green wrote the check on Oct. 11, 1983, and that Holland then hand-delivered it to Hughes. But Samuel L. Halsey, the university's internal auditor, produced a memo from his files showing that Green actually wrote the check on Oct. 7, but had dated it Oct. 11.

Holland and Halsey said that after Green's reimbursement, they considered the stereo his personal property. They and other witnesses testified that they knew nothing of additional financial arrangements concerning the stereo, and said they had no involvement in the subsequent purchase of the television.

But Cropp testified that on Oct. 13 he cashed a $1,800 check on the mayor's Mini Art Gallery fund, gave Green $1,400 to reimburse the UDC Fund and placed the remaining $400 in petty cash accounts for the mayor's office.

Cropp also testified that he wrote the $1,994.90 check that bought the Hitachi projection television. The check was written on the mayor's Cesaire Fund account, Cropp said, to avoid any possible embarrassing publicity, but the money to the purchase came from the mayor's ceremonial fund.

Cropp said Green promised to repay the money to the mayor's office through interagency transfers from UDC accounts and to leave the equipment at the university-owned president's residence when he left his post. Cropp said he did not know whether the reimbursements were ever made.

Michael Mullins of Mullins Transfer & Storage Co. testified that his company moved the stereo and television first to the Greens' apartment at 4301 Massachusetts Ave. NW and then into the company's storage facility to await shipment to Ohio. The equipment was seized by the FBI two weeks before the goods were to be moved, Mullins said.