The invention provides a bottom shell assembly sealing device of an air conditioner. The bottom shell assembly sealing device comprises a bottom shell, an angular frame used for supporting and fixing an evaporator, and a shaft sleeve assembly used for supporting blades. The angular frame is arranged on the bottom shell. The shaft sleeve assembly is also arranged on the bottom shell and disposed between the bottom shell and the angular frame. The bottom shell and the angular frame are matched to form a cavity for containing the shaft sleeve assembly. An opening is formed in one end of the cavity and faces the inner side of the bottom shell. The shaft sleeve assembly is surrounded in the cavity. The invention further relates to the air conditioner. According to the bottom shell assembly sealing device of the air conditioner and the air conditioner, the bottom shell and the angular frame are matched to form the cavity for containing the shaft sleeve assembly so that the matched position of every two of the bottom shell, the shaft sleeve assembly and the angular frame on one side of an air duct can be effectively sealed, one side of the air duct is completely sealed, the hidden danger that hot air permeates into the air duct from the area is completely prevented, and the defective condition that condensation water is blown out of the air duct is relieved.