A belt transmission mechanism, comprising four belt rollers (4), each belt roller (4) being sleeved with a belt pulley (5), a belt (3) being sleeved on the outer side of the four belt pulleys (5) and an electric motor (6) being provided inside the belt (3); a ball screw (10) has a synchronizing wheel (8) at one end thereof; a transmission belt (7) is sleeved on the rotary shaft of the electric motor (6) and the synchronizing wheel (8); the ball screw (10) is fixed at two ends thereof by screw fixing frames (11) and passes through a movable clamping device (15), the movable clamping device (15) having a cylinder (16) used for the movable clamping device thereon and having a first fixed clamping device (9) and a second fixed clamping device (13) at either side thereof, the first fixed clamping device (9) having a cylinder (12) used for the first fixed clamping device, the second fixed clamping device (13) having a cylinder (14) used for the second fixed clamping device; compaction ends of the cylinder (12) used
