Former CIA agent Edwin P. Wilson was indicted by a federal grand jury in New York yesterday on obstruction-of-justice charges in an alleged scheme to arrange the slayings of an unspecified number of persons, including his former wife and four persons expected to testify against him in future trials.

The grand jury alleged that Wilson, a multimillionaire who left the agency in 1971, offered $1.5 million in bribes to two fellow inmates in a federal penitentiary in Otisville, N.Y., to arrange for the slayings of the witnesses and his former wife Barbara, Manhattan Assistant U.S. Attorney Eugene N. Kaplan said yesterday.

Wilson, who has been sentenced to 32 years in prison after convictions in Alexandria and Houston on charges involving illegal shipments of weapons and explosives to Libya, was indicted last February on charges of offering a fellow inmate in a Manhattan jail $1.2 million to kill two Washington prosecutors and six other persons. Yesterday's charges are an expansion of that case, currently set for trial Sept. 12.

The indictment yesterday alleged that Wilson offered the two fellow prisoners in Otisville money "to kill and to hire and arrange for assassins to kill" people expected to testify against him in future trials.

Kaplan said the grand jury charged that Wilson offered to pay the two prisoners to arrange the slayings of his former wife and three witnesses who figured in his first two trials: Reginald Slocombe, a former business associate; Jerome S. Brower, a California explosives dealer, and John Heath, a former employe of Wilson's in Libya. He said the indictment alleges Wilson offered the men $250,000 for each death.

Kaplan said Wilson also offered the two Otisville prisoners $500,000 to arrange for the death before next month's trial of Wayne Trimmer, the convicted murderer who told the FBI of Wilson's alleged slaying scheme earlier this year. The men were allegedly offered $100,000 if Trimmer were killed after the trial, Kaplan said.

Kaplan said the indictment also alleged that Wilson tried to arrange for the deaths of other, unnamed persons.

Kaplan said he did not know if the Sept. 12 trial would be postponed as a result of the new charges.