A 25-year-old Southeast Washington man is to spend at least the next 54 years in prison after being sentenced yesterday in D.C. Superior Court for the slaying of a Korean grocer two years ago.

Ulysses Jones Jr. was sentenced to 20 years to life by Judge Fred B. Ugast on a first-degree murder conviction in the shotgun slaying of Boo Yeol Park at the Fort Drum Market in Southwest on Dec. 13, 1979.

According to testimony, Jones and an accomplice robbed the grocer of $60, then killed him with a shotgun.

Last year, Ugast sentenced Jones to 20 years to life in the murder of an off-duty Secret Service officer, George I. Coaxum, outside a Northwest bar on Jan. 11, 1980. Jones and an accomplice stole Coaxum's wallet, then shot him in the back as he attempted to flee, according to prosecutors.

Jones also is serving 10 to 30 years on an unrelated conviction of assault with intent to kill, and additional prison sentences for lesser offenses.

At yesterday's sentencing, assistant U.S. attorney Harold L. Cushenberry said Jones "took part in two of the most cold-blooded murders I have seen in my six years in the office."

Jones, he said, "is a man marked by savagery, viciousness and brutality."

Defense attorney James M. Doyle had asked for a shorter sentence, arguing that the parole board should be given a chance to reevaluate Jones when he reaches middle age.

Jones' sentences are to run consecutively. According to Cushenberry, Jones will be 79 before he is eligible for parole.

Jones, who has previous convictions for robbery and escaping from prison, was convicted in 1980 of assault with intent to kill and assault with a dangerous weapon in connection with an incident Oct 11, 1979, at Strawberry's Pool Hall, 124 15th St. SE.

Following an argument at the hall with another man, William L. Riley, Jones pulled a gun and shot at Riley and his wife, shattering three windows in their car, according to prosecutors.

Jones' accomplice in the shooting of Park, Gregory Britt, 26, and his accomplice in the Coaxum killing, Ricky D. Bryant, 23, each have been convicted of first-degree murder and sentenced to 20 years to life.

In asking for the maximum sentence against Jones yesterday, prosecutor Cushenberry said: "He has to answer for what he has done."