Fairfax County Deputy Police Chief Kenneth R. Wilson yesterday said he will retire from the police force effective March 23 to seek the Democratic nomination for a four-year term as sheriff.

Wilson thus becomes the second person to announce publicly his intention to seek command of the embattled sheriff's office. There are three other persons who also are expected to run for the job.

Asked why he would give up his $36,500 job as deputy police chief to run for sheriff, Wilson said, "I'm familiar with the incarcerated." He added that the county sheriff's job "is more lucrative" than his present postion.

If Wilson is elected sheriff, his annual income, combined with his expected retirement pay of $20,000, will net $55,000 to begin with, about $18,500 more than his current salary. The pay for the sheriff's job increases by steps to a maximum of $48,000 after 10 years.

The job, however, has had its problems. For the past year, the county sheriff's department, led by Sheriff James D. Swinson, has been embroiled in controversy. On two occasions, the department has been investigated by county Commonwealth's Attorney Robert F. Horan Jr. at the request of the county board of supervisors.

The first investigation, concluded in August, found a "widespread" pattern of inmate misuse by deputies who permitted inmates to leave the jail for conjugal visits and who illegally used prisoners to do work outside the jail.

The second investigation was initiated last December, when an inmate died two days after he was taken from the jail to a state hospital. The inmate was the third black in six months to die after being confined in the jail.

Horan found that the inmate, Donald L. Ferguson, was not treated in accord with the jail's own rules. His death angered the county's largest black community, Gum Springs, where Ferguson grew up.

Last month, the county supervisors called for a detailed study of the jail operation, to be conducted by a group with no ties to county government.

Wilson yesterday said he will refuse to comment on recent events involving the county's sheriff department as long as he remains with the police department. He said he will comment on these problems once he has retired.

As deputy police chief, Wilson has been responsible for general law enforcement in the county. He has supervised the operations of more than 1,000 department employes, 300 of whom are civilians.

If elected county sheriff, Wilson would oversee about 140 employes who are responsible for custody of prisoners, court security and the serving of court summonses.

Swinson, who has been sheriff for 16 years, is not seeking reelection.

Horan, a Democrat, said he thinks Wilson "would male an excellent sheriff. He's a real talent. He's been in all phases of police work."

However, Myron L. Greenquist, a critic of the sheriff's department who is seeking the Republican nomination for the job, but has not yet formally announced his candidacy, discounted the importance of law enforcement in running the sheriff's office. "The sheriff office and jail don't require a law enforcement background," he said.

Greenquist, a former chief deputy sheriff fired by Sherriff Swinson, said, "Everybody is getting in the race. They all have the answers. Only Bud Greenquist knows which deputies must leave to clean that place up... I know how they [deputies] operate."

Wilson declined to respond to Greenquist's comments.

Wilson joined the county police force as a patrol officer in September 1956, after serving four years in the Air Force. He also has been a member of the motorcycle squad, a detective, station commander and deputy commander of the criminal investigations division.

In 1972, he commanded the services bureau, which includes budgeting, planning, personnel administration and the emergency operations center. He was promoted to deputy police chief in 1975.

Howard L. Miller Jr., director of security operations for Air France Concorde at Dulles International Airport, already has announced his plans to seek the Republican nomination.

M. Wayne Huggins, who replaced Greenquist as Swinson's chief deputy, and Terry Armstrong, a former senior corrections officer for the D.C. Department of Corrections, also are expected to run. Huggins is a Republican and Armstrong is a Democrat.