Buddy Earl Justus, a murderer on Virginia's Death Row who last month said he was ready to die in the electric chair, told a state judge today he had changed his mind.

The 30-year-old Justus, convicted of murdering women in three states and sentenced to death in Florida and Georgia as well as Virginia, reached his decision yesterday afternoon after talking with his Atlanta attorney. Today, handcuffed and dressed in blue jeans, Justus told Circuit Court Judge Russell Carneal he wanted to pursue his petition for habeas corpus, an appeal process that could keep his case in the courts for a long time.

"He wants to live," said Rob Spessard, one of Justus' three Virginia lawyers, after a brief court hearing in the Williamsburg-James City County Courthouse.

In a petition he drafted himself and sent to the local court Jan. 17, Justus asked that his execution be "conducted as soon as possible." His would have been the second electrocution in Virginia in two decades since the Supreme Court revised constitutional standards for the death penalty.

On Aug. 10 Frank J. Coppola, an ex-policeman convicted in the beating death of a Newport News housewife, was executed at the Richmond penitentiary after he dropped his appeals.

Lawyers said today Virginia is not likely to see an involuntary execution in the near future, since the state's 19 death row inmates are still far from exhausting their appeals.

Justus, convicted in 1979 in the murder and rape of a pregnant nurse, had his original death sentence overturned by the Virginia Supreme Court a year later because one of the potential jurors in the trial had shown a bias against him. He was convicted again in 1980 at a second trial held here.

A native of Niagara Falls, N.Y., Justus has also been convicted of murdering women in Georgia and Florida during a four-day spree in October 1978 that ended in Montgomery County, Va., with the shooting of Isa Mae Moses, a 21-year-old nurse who was expecting to give birth in 10 days.

Justus' attorneys said today he sought his own execution because of the conditions on death row in a state prison in Mecklenburg County. "Death rows are designed to prepare you for death and some death rows do that very well," said Marie Deans, of the Virginia Coalition for Jails and Prisons, a newly formed inmate advocacy group.