The invention discloses a parking device and a stereo garage thereof. The device comprises a rack, a lifting mechanism and a supporting frame. The rack comprises two oppositely-arranged first supporting arms, a beam connected with the two first supporting arms and second supporting arms; the lifting mechanism comprises a rotating rod, a connecting plate, a transverse rod, a first driving assemblyand a second driving assembly, one end of the rotating rod is rotationally connected with the second supporting arms, the other end of the rotating rod is rotationally connected with the connecting plate, the connecting plate is sleeved with the transverse rod, the connecting plate drives the transverse rod to rotate, the first driving assembly is fixedly connected with the transverse rod, the second driving assembly is connected with the first driving assembly, the supporting frame is fixedly connected with the second driving assembly, so that the number of underground garages is increased, the requirement of vehicle owners is met, the space utilization rate is increased, the floor area of the parking lot is completely utilized, and land resources are saved.