Classified documents allegedly sold to the Soviet Union by accused spy Christopher Boyce may have only been meant to provide the Russians with purposely misleading "disinformation" and were not essential to national security, former CIA agent Victor Marchetti testified today.

Marchetti, co-author of the conversial book "The CIA and the Cult of Intelligence," appeared as the final scheduled defense witness in the federal trial of Boyce, 24, who along with Andrew Lee, 25, is charged with selling classified documents about the CIA's "Pyramider" communications project to Soviet agents.

Marchetti's testimony was secured to support the contention of Boyce's lawyer, William Dougherty, that the Pyramider documents were not of a high national security nature and thus do not merit Boyce's prosecution under the espionage act. Boyce and Lee are the first persons charged under the act - which carries a possible life sentence - since the 1953 convickions of Ethel and Julius Rosenberg.

Marchetti, 47, an employee of the Central Intelligence Agency from 1955 to 1969, says he firest heard of Pyramider while serving in the Cia budget office in 1968. The program, he said, at that time involved putting a satellite into orbit to serve as a communications link between CIA agents in unfriendly nations ad CIA headquarters at Langley, Va.

Boyce and Lee are accused of selling the Soviets information on a $66,000 study conducted in 1972 at TRW, Inc., a large Redondo Beach, Calif., electronics firm. For an estimated $70,000, the government claimed, Boyce, a documents clerk at TRW and son of a former FBI agent, smuggled Pyramider documents to alleged co-conspirator Lee, who then handed them over to Soviet officials.

Today Marchetti said Pyramider was from the beginning a "filmsy concept." His superiors at CIA "never did have much faith in it," Marchetti said of the project, long since dropped. "They questioned if it was feasible at all."

Marchetti said his CIA superiors considered Pyramider an attractive ay "to show our ingenuity" to the congressional committee controlling their budget: "Even if it didn't work well, we thought it might get our budget passed."

Marchetti claimed that Pyramider was considered valuable also as a possible vehicle for feeding "disinformation" to unwitting Soviet agents. "It could be used to send phony data down to where the Soviets would go bananas trying to figure out what the information meant - when it actuall y meant nothing. It was a confusion-like disinformation," he said.

Under cross -examination by Assistant U.S. Attorney Joe Levine, Marchetti acknowledged that Pyramider had changed between the time he was in the CIA and the period of Boyce's alleged document sale. The TRW study, for instance, concerned a project with three stationary satellites as opposed to the original proposal involving a single orbiting one.

Shortly after dismissing Marchetti from the stand, Judge Robert Kelleher cleared the court of press, public and jurors. After a brief conference with attorneys, Kelleher announced that the trial would continue and probably conclude Tuesday.

The trial of Andrew Lee, who is charged with actually passing the documents to the Soviet agents, is scheduled to begin Wednesday morning, following the Boyce proceedings.

Lee and Boyce were arrested on espionage charges last December. While the cases against them appear to be basically the same, their lawyers have split since Boyce's trial began less than two weeks ago. Lee's attorney, Kenneth Kahn, accused the Boyce attorneys today of presenting a weak case and charged them with being part of CIA-directed plot to protect other CIA activities.

"There's no question about it, the CIA is running this trial," Kahn said after today's proceedings. "They're running Boyce through first in order to make our case look weak." Kahn accused Boyce, who has been sitting impassively throughout, of being himself an agent of the CIA.

Like Boyce's attorney, Kahn has subpoenaed Marchetti. Marchetti is also working as a consultant in the Baltimore trial of Edwin G. Moore II, a former CIA employee accused of attempting to sell classified material to the Soviet Union.

Marchetti, who requires and has obtained CIA clearance to testify at these trials wonders whether his former employers have a hidden motive for allowing his testimony. "I'm beginning to get a bit uncomfortable about this," Marchetti said after today's court session. "Maybe they want to hurt my credibility by having me rush to the defense of every rotten red pinko and defector they can find."