Aslov previously served as Dushanbe's representiative at the United Nations.
Rahmon, who was reelected on November 6, also named new finance and transport ministers.
Abdusalom Qurbonov, who was the head of the construction department of the presidential administration, was appointed finance minister.
Khayrullo Asoev, who was the chairman of Roghun hydropower plant, became transport minister.
Rahmon has ruled Tajikistan since 1992.