The invention discloses a crown block hydraulic system and a control method thereof. The crown block hydraulic system comprises a truss, a block body, at least two working devices, an actuator, and a controller; the truss is arranged to extend in the horizontal direction, and is movable in the vertical direction. The block body is movably disposed at the bottom of the truss in the horizontal direction. At least two working devices are respectively connected with the block body bottom liftably through at least two hydraulic cylinders; each of the hydraulic cylinders is provided with at least three gears of second gear, first gear, and stop; the hydraulic cylinders are liftable between a highest position and a lowest position. The actuator is in signal connection with at least two hydraulic cylinders to respectively control the operation and stop of at least two working devices. The controller is in signal connection with the actuator to control at least two hydraulic cylinders. The crown block hydraulic system of the invention can operate more stable and reliable.