The invention provides a power-operated trolley, which comprises a frame, a steering axle, a storage battery box, an electronic control device, a driving motor, a steering device, a speed reduction box, a driving axle, a wheel assembly, an emergency braking device and a parking braking automatic control system, wherein the driving motor is provided with an electromagnetic brake, the driving axle is provided with a hydraulic brake, the emergency braking device comprises a fixing cross beam, a movable cross beam, emergency switches, springs and rotating handles, the number of the emergency switches, the springs and the rotating handles are respectively two, the two ends of the two rotating handles are respectively hinged to rotating handle hinges on the fixed cross beam and rotating handle hinges on the movable cross beam, and the connecting lines of four hinging points form a parallelogram. When the power-operated trolley is used for performing transporting operation with large carrying load, the energy consumption is low, the cost is low, driving braking and parking braking are effectively ensured through combined braking of hydraulic braking and electromagnetic braking, the safety performance is high, the specific parallelogram mechanism of the emergency braking device effectively ensures braking in emergency situations, and the safety of carried goods is effectively ensured.