The present invention provides a bookbinding system, which is used to solve the following technology problem. The adhesive amount in the adhesive groove is detected through detecting that the adhesive amount has been reduced to certain degree, due to the change of amount is multi-stage, also it is hard to detect continuously, in minitype coating device, and the using amount of adhesive affects the liquid surface change which adds difficulty to coat uniformly. The bookbinding system of the present invention calculates suitable replenishment ratio and that corresponding to paper stack for adhensing based on paper stack information. The information of replenishment ratio is transferred through communication between image forming device and bookbinding device.