The invention discloses an electric pulley mechanism for a sky rail system. The electric pulley mechanism comprises a pulley device, a driving device and a suspension device, the pulley device comprises a base, two movable blocks which correspond to each other left and right are rotatably arranged on the upper end face of the base, pulley blocks which are vertically arranged are fixedly arranged on the two movable blocks which correspond to each other left and right, clamping blocks are fixedly arranged on one sides of the two movable blocks which correspond to each other left and right, and asteering wheel is arranged in the middle of the clamping blocks. The driving device comprises a hood shell, a suspension type supporting seat is arranged in the hood shell, a driving wheel is arranged on the suspension type supporting seat through a rotating shaft, the upper half portion of the driving wheel is arranged outside the hood shell, a driving motor is arranged in the hood shell, an output shaft of the driving motor is connected with the rotating shaft through a coupling sleeve, and a clutch device is further arranged in a hood. According to the electric pulley designed in the scheme, the driving wheel is driven by the driving motor, so that the whole pulley mechanism automatically translates in the rail, and meanwhile, the clutch device can be opened, so that the pulley mechanism can manually translate in the rail.