Convicted former CIA agent Edwin P. Wilson and his son, Erik, 22, were indicted by a federal grand jury in New York yesterday on charges of offering $1.2 million for the assassination of two Washington prosecutors and six other persons as the elder Wilson awaited trial last fall.

The indictment said Edwin Wilson, a millionaire who left the agency in 1971, was in custody at the Metropolitan Correctional Center on Manhattan's Lower East Side in November, when he approached a fellow inmate about hiring a hit man. The prisoner, Wayne Trimmer, a convicted murderer, put Wilson in touch with an FBI agent posing as a hired killer, the grand jury charged.

Erik Wilson, who is charged in the indictments with delivering a $9,800 down payment for the murders in a LaGuardia Airport motel men's room last month, surrendered yesterday to federal agents in New York. The younger Wilson, who lives in a Northwest Washington town house owned by his father, was ordered held under $500,000 bond.

The tall, gray-haired Wilson, portrayed by prosecutors as a former spy who turned into a renegade arms dealer motivated by greed, is serving a 15-year sentence imposed by a federal judge last fall in Alexandria for smuggling weapons to Libyan intelligence agents. He is scheduled to be sentenced on Friday in Houston, where he was convicted two weeks ago of smuggling explosives.

A third trial in Washington, on murder conspiracy charges involving a Libyan dissident, is set to begin on Feb. 28.

In the New York case, both men face maximum sentences of life plus 177 years as well as $2 million in fines if convicted on all 15 counts in which they both are charged. Edwin Wilson is accused in two further counts of witness tampering in connection with alleged death threats against a former employe who testified at the Houston trial.

Prosecutors have asked a federal judge in Houston to classify the elder Wilson a "dangerous special offender," which could add another eight years to the 17-year prison term he faces there.

The two prosecutors allegedly targeted for death were identified as E. Lawrence Barcella Jr. and Carol Bruce, both of the U.S. Attorney's office in the District.

Also on a hit list which Edwin Wilson allegedly wrote out were four witnesses who figured in his first two trials. They are Ernest Keiser, a Northern Virginia businessman who helped lure Wilson out of Libya last summer; Reginald Slocombe, a former business associate who testified under a grant of immunity from prosecution; Edward Coughlin, a New York lawyer who managed Wilson's financial affairs, including Swiss bank accounts; and Jerome S. Brower, a California explosives merchant.

Yesterday's indictment charged Wilson later added two more names to the list: Raphael Quintero, a Cuban exile whom Wilson allegedly tried to recruit to assassinate the Libyan dissident, and Francis Heydt, a former business associate who prosecutors said owed Wilson $3.2 million.

The grand jury alleged Wilson offered $250,000 for the death of each prosecutor, $500,000 for Heydt's assassination and $50,000 for each of the others.

Wilson has been held under tight security, without telephone access, since the alleged plot was uncovered. His lawyer, Herald Price Fahringer, said recently Wilson's cell is lighted around the clock.