Susan L. Mullis, who was convicted last month of murdering her husband in 1983 on a remote dirt road in Fairfax County, was sentenced yesterday to 22 years in prison.

Fairfax Circuit Court Judge F. Bruce Bach, who imposed the sentence, called the crime "an absolutely cold-blooded execution-type murder." He told Mullis that the jury that convicted her, recommending the 22-year prison term, accorded her "probably more consideration than you were entitled to." Under Virginia law, judges may not increase sentences recommended by juries.

Mullis, a 29-year-old former waitress who has maintained she is innocent, stood expressionless as Bach sentenced her, then smiled slightly at her attorneys as she was led from the courtroom. One of her attorneys, Glenn H. Silver, said she will appeal the verdict.

Her sentence consists of 20 years for first-degree murder, the minimum for the crime, and two years for using a firearm to commit a felony. She could be eligible for parole by 1989.

Her husband, Michael L. Mullis, a 29-year-old Woodbridge pharmacist, was shot to death July 23, 1983, on an isolated part of Kincheloe Road near Clifton, where he had driven with his wife.

Susan Mullis told police on the night of the shooting that she went into the woods to relieve herself, heard three shots, returned to find her husband shot, then ran to get help. Police found no murder weapon and no witnesses, and prosecutors relied almost exclusively on circumstantial evidence to convict the widow.

A former boyfriend testified that Susan Mullis had asked him to arrange the murder of her husband or to do it himself. She testified that she was only joking.

The Mullises were scheduled to be legally separated the week after the slaying, according to testimony, at which point Susan Mullis would no longer have been the beneficiary of $225,000 in insurance on her husband's life.

Susan Mullis' conviction will prevent her from receiving the insurance money.

Bach set bond at $100,000 pending her appeal. Mullis is being held at Fairfax County jail.