A lawn mower comprises a driving assembly, an impact protection assembly, a transmission assembly and a cutting assembly. The impact protection assembly comprises a first bearing seat and a second bearing seat which are mated with each other, and an elastic member and a ball which are positioned between the first bearing seat and the second bearing seat. The first bearing seat is provided with a protrusion. When the driving assembly performs driving, the ball is pushed by the elastic member to be in contact with the protrusion of the first bearing seat, so that the transmission assembly and the cutting assembly are driven to rotate synchronously. When the resistance received by the cutting assembly is greater than a preset value, the elastic member is continuously compressed and the ball passes over the protrusion, and a relative rotation between the transmission assembly and the driving assembly occurs.