The invention provides a lawn mower, which comprises a driving assembly, an impact protection assembly, a transmission assembly and a cutting assembly. The driving assembly comprises a motor. The impact protection assembly comprises a pressing member and an elastic piece. The pressing member presses the elastic piece towards the transmission assembly to drive the transmission assembly and the cutting assembly to synchronously rotate with the motor shaft. When the resistance of the cutting assembly is greater than a predetermined value, A relative rotation is generated between the transmission assembly and the motor shaft. According to the lawn mower, the impact protection assembly is arranged between the driving assembly and the transmission assembly, when the reaction force upon the cutting assembly from external obstacles is greater than the friction force of the impact protection assembly, the transmission assembly and the motor shaft rotate relatively, and the transmission assembly is protected.