The invention relates to a cover clamping book discharging mechanism of a glue binding machine, which can discharge books automatically, reduce the workload and improve the working efficiency. The cover clamping book discharging mechanism comprises a cover clamping bedplate, front and rear deflector shafts, front and rear deflector rods, front and rear fan-shaped plates, and front and rear clamp plates, wherein a rectangular opening (40) is arranged in the middle part of the bedplate (1); a splint (4) is arranged below the front clamp plate (2), and a front guide key (34) arranged in a guide slot of the splint is connected below the front clamp plate (2); a front guide key seat (3) which corresponds to the front deflector rod (141) is connected below the front guide key; the two sides of the splint are respectively connected with an upper slide block (3) and a lower slide block (9) which are fastened at two sides of the rectangular opening of the cover clamping bedplate; a front clamptension spring (35) is connected between the guide key seat and splint; a book discharging guide hopper (20) whose upper part is vertical and lower part declines in an arc shape is arranged on a stand; and the upper opening of the book discharging guide hopper corresponds to the rectangular opening of the cover clamping bedplate. The invention is used for automatically discharging glue binding cover and books and thin books bound with the glue binding cover from the glue binding machine.