The invention discloses a screw lever type clamping mechanism which comprises a supporting table, a locking part and a driving part. The supporting table is of an isosceles trapezoid structure, a connecting plate and a supporting plate are arranged on one side face of the supporting table, and a slide rail is arranged in the supporting table. The driving part comprises a screw, a nut, a cap-shaped object, a first lever, a first pin, a first connecting member, a spring and second connecting members, wherein the screw is connected to the supporting plate through threads, the nut and the cap-shaped object are connected to the screw, the cap-shaped object is arranged above the nut, the first lever is connected to the connecting plate through the first pin, one end of the first lever abuts against the cap-shaped object, the other end of the first lever abuts against the first connecting member, the first connecting member is in sliding connection with the slide rail, the left end and the right end of the first connecting member are respectively connected two second connecting members through pins, and the spring is connected between the first connecting member and the slide rail. The locking part comprises a clamping claw provided with a limiting groove, wherein the clamping claw is connected with the second connecting members through pins. The screw lever type clamping mechanism is firm in structure and adjustable in locking pressure.