Dolores Ibarruri, the fiery Communist leader who became a mythical figure during the 1936-39 civil war, returned quietly to Madrid tonight from Moscow, ending 38 years of exile.

The silver-haired "La Pasionaria," 81, was whisked off the Soviet Tupolev airliner moments after landing in Barajas airport here and shunned any public demonstrations, Ibarruri, who is president of the recently legalized Communist Party, was driven immediately to a Madrid apartment to greet other Communist leaders.

The party and the government arranged for the quiet reception. A few hundred Communists, however, ignored strict party orders against an airport demonstration and gathered there with party flags. Waving their banners, they shouted "Viva la Pasionaria" and "Si, si, si, Dolores is in Madrid." Several aged Communists shed tears.

The restrained arrival was enforced to avoid enraging rightists, who consider her the "most vicious enemy of the Franco regime and Spain" because of her uncompromising stand for nearly four decades. Not only is she antimonarchist, but she is not keen on the Eurocommunist line adopted by the Spanish Communist Party under the leadership of General Secretary Santiago Carrillo.

A native of the Basque region, she became a Communist in 1920 and was active in the harsh mining region of Asturias. She was jailed repeatedly for her political activities. With the fail of the monarchy in 1931and the advent of the republic, she rose quickly in the small and aggressive party. In 1936 she became a deputy in the republican Parliament and stunned fellow legislators by wearing rope-soled canvas shoes to the legislature.

She gained worldwide fame on July 18, 1936, when her reply to the nationalist military uprising of the late dictator Francisco Franco was, "No pasaran " ("They shall not pass.") From that moment she harangued republican troops, went on the radio repeatedly, and visited the wounded. She berated republican leaders for lack of determination. Her strong features, black dress and impassioned speeches won her worlwide fame.

She fled to France and then to the Soviet Union after the fall of the Republic.She was made party president in 1960.

A major figure in world communism, she is running in next month's elections for a seat in Parliament in Ovideo, the Asturian city she represented during the republic. She is scheduled to address a rally there Sunday.

Before leaving Moscow with Irene Falcon, her secretary, she was given a high-level Soviet sendoff. Mikhail Suslov, top Politburo official, and Boris Ponomarev, who is charge of relations with nonrulung Communist parties, accompanied her to the plane.