Acting Gov. Blair Lee III appointed Rita C. Davidson to Maryland's Court of Appeals yesterday, making her the first woman appointee in the 200-year history of the state's highest court.

Davidson, a Montgomery County resident who currently sits on the court of Special Appeals, the state's second highest court, has been known throughout her political and judicial life as an articulate, intelligent woman who speaks her own mind, according to colleagues and acquaintances.

One Maryland trial judge noted that the Brooklyn born, Yale-educated Davidson is "vigorous in her views and has expressed herself in dissenting opinions." Some of those have set the tone for later decisions by the Court of Appeals she will now join.

During her six years on the Court of Special Appeals, she has been a strong advocate of defendants' rights, particularly to a speedy trial.

During two years in the early '70s she was one of the most controversial and outspoken members of then Gov. Marvin Mandel's cabinet, fighting for higher welfare payments for the poor and larger budgets for what she considered underfunded welfare agencies. Chief Judge Richard C. Gilbert of the Court of Special Appeals said she is "pleasant, bright articulate...and has a mind of her own.She will do a good job."

The 50-year-old Davidson said yesterday it is "a singular honor and a somewhat awesome experience to contemplate being the first woman on the highest court in my state."

Lee said Davidson's sex was not a "controlling" factor in his selection of her from among four nominees to fill the vacancy on the seven-member court created by the death last October of Judge Irving A. Levine, also of Montgomery County.

"The choice was not an easy one because of the exceptionallly high qualifications of the nominees....Nevertheless, I have concluded that Judge Davidson is unsurpassed among them in terms of scholarship, intellectual capacity and breadth of experience," Lee said.

Davidson, who graduated from Goucher College in Maryland and earned her law drgree at Yale, said she had wanted to be a judge since she was 6 or 7 years old. She recalled that her parents, both Russian immigrants who started but failed to complete medical training, had high ambitions for their children.

"When other little girls were saying they wanted to be nurses or teachers or mommies, I was saying I wanted to be a lawyer, and I knew it was also a good thing to be a judge," Davidson recalled.

After earning her law degree in 1951, she practiced in the District of Columbia and later in Montgomery County, where she became active in Democratic politics, and served as a zoning hearing examiner, a member of the Maryland-National Capital Park and Planning Commission and in Mandel's cabinet. She was named to the Court of Special Appeals in 1972.

Some of her most important decisions there, according to legal acquaintances, were in the areas of administrative law, product liability, and criminal procedures.

In the field of product liability, in 1974, she wrote an opinion in favor of a woman who lost an eye after a soda bottle exploded in a supermarket. Although it could not be proved whether the supermarket or the soda supplier was the party at fault, the court held for the first time that the woman was entitled to collect from the one probably to blame.

Davidson dissented in a 1975 case involving criminal liability, asserting that a defendant convicted of narcotics violations was denied his constitutional right to a speedy trial. Her dissent later formed the basis of a Court of Appeals opinion, reversing the lower court ruling.