Disclosed is an elevator fall-prevention mechanism with a compound locking sliding block. The elevator fall-prevention mechanism comprises a crank, a connection rod, the locking sliding block, a control rod and stop blocks. The locking sliding block is arranged on a lift car frame and can slide horizontally. One end of the connection rod is connected with the locking sliding block, and the connection rod can swing with the corresponding connection point as the pivot. The other end of the connection rod and one end of the crank are connected and can swing mutually with the corresponding connection point as the pivot. The other end of the crank is connected with the lift car frame, and the crank can swing with the corresponding connection point as the pivot. One end of the control rod and the crank are connected and can swing mutually with the corresponding connection point as the pivot. The other end of the control rod is arranged in a lift car. The stop blocks are arranged on a well wall. Floating plates are arranged on the upper surfaces of the stop blocks and connected with the stop blocks through a set of springs. The locking sliding block comprises a metal layer and an annular high-manganese steel wire mesh arranged in the metal layer. When an existing fall-prevention device loses efficacy, people in an elevator can brake the elevator manually, and thus self rescue of the personnel in the elevator is achieved.