A Maryland special prosecutor said yesterday he has determined, following a five-month investigation, that there was nothing illegal about a $2,000 loan to a close aide of Montgomery County Executive Charles W. Gilchrist.

The investigation, requested last May amid continuing controversy over the county's Department of Liquor Control, focused on a January 1980 loan from former liquor firm executive Charles Buscher to Gerard Evans, then a special assistant to Gilchrist. At the time, Evans, who later resigned, and Gilchrist were recommending that Frank Orifici, the husband of Buscher's niece, be selected for the deputy directorship of the liquor agency.

That prompted Montgomery State's Attorney Andrew Sonner and others to call on the special prosecutor's office "to begin an investigation of any possible criminal law violations."

Gerald C. Ruter, an assistant special prosecutor for the Maryland office that investigates politically sensitive cases, said yesterday he has "determined that there was no intent on the part of Mr. Buscher or Mr. Evans to violate the laws of the state . . . As far as I'm concerned, the matter is closed."

Earlier this week, Robert P. Trout, a lawyer hired by the Montgomery County Council, also concluded that the loan was legal but added that "Evans should have avoided any involvement in the appointment of the deputy . . . or he should not have approached Mr. Buscher for a loan."

A similar issue was raised yesterday by state Del. Luiz Simmons (R-Montgomery), who said he was satisfied with Ruter's work but added that "the larger issue is still the whole question of cronyism, what I consider to be clear and conspicuous acts of impropriety, a top figure of the administration receiving a loan. It remains a question of concern."

Ed Rovner, special assistant to Gilchrist, parried Simmons statement by saying, "the candidate Simmons, like other Republicans, changes the charges every day. As each charge is disproven, another is offered.

"When the loan came to Gilchrist's attention, he asked for Evans' resignation and got it on the same day. Gilchrist considered it to be an improper act," Rovner added.

Ruter's investigation was only one of several prompted by a 1 1/2-year-old flap over the agency that has monopoly control over the distribution of alcoholic beverages in the county. None has uncovered any illegal acts. Still unresolved are two issues being studied by the county's Merit System Protection Board.

Gerard Evans, now a full-time student at the University of Baltimore Law School, said "I'm very happy about it . . . They always say hindsight is 20-20, but if I knew then what I know now I probably wouldn't have taken the loan. But who could ever perceive that such a debacle would ensue?"