A back knocking mechanism comprises a stander (1), a knocking force regulating motor (2), a knocking force regulating deceleration device (3), a worm (4), a main motor (5), a main motor deceleration device (6), a small gear (7), a convex disc (8), a slide rod (9), a concave disc (10), a transitional disc (11), a large gear (12), a knocking head (13), a knocking arm (14), a turbine (15), a transmission shaft (16) and a volute spring (17). The knocking force regulating motor (2) drives, through the knocking force regulating deceleration device (3), the worm (4) and the turbine (15), the volute spring (17) to move relative to the transmission shaft (16) to regulate a knocking force； and the main motor (5) converts continuous motion of the main motor (5) into swinging of the transmission shaft (16), through the main motor deceleration device (6), the small gear (7), the large gear (12), the convex disc (8), the slide rod (9), the transitional disc (11) and the concave disc (10). Also disclosed is a knocking method. The back knocking mechanism is small in size, and safe and comfortable to use.
