An actuator with multi-stage gears includes a worm gear shaft driving assembly having a worm gear shaft, an electric motor having a transmission shaft, an annulus gear arranged between the worm gear shaft and the transmission shaft, and a plurality of multi-stage gears. The annulus gear includes an inner gear and a moving end actuated cooperatively with the inner gear on two ends thereof. The moving end is connected to and driving the worm gear shaft to rotate; each multi-stage gear is arranged between the transmission shaft and the inner gear; each multi-stage gear includes a first and a second outer diameter portions. The outer circumferential edges of the first and second outer diameter portions includes a helical gear engaged with the transmission shaft and a spur gear engaged with the inner gear respectively. Therefore, the actuator has merits of simplified components and reduced volume.