The invention provides a printer with a printing quality detecting module, comprising: a printing quality detecting module comprising a supporting plate, a photo-sensor, a light barrier, a light source, and a communication port; the photo-sensor, the light barrier and the light source are fixedly installed at the supporting plate; the light barrier is positioned between the photo-sensor and the light source; and the communication port is connected with the photo-sensor. The invention has the following advantages that: a printing quality detecting module is designed creatively; the light source of the printing quality detecting module is used for emitting detecting light; the detecting light is reflected by printing paper, then received by the photo-sensor, and finally transformed into detecting signal; and the printing quality is judged according to the detecting signal to find the unqualified printed note and inform operators and an upper computer by signals such as sound, light, and electricity, thereby increasing the integral printing quality of the printer.