The invention discloses a quality monitoring method, device and system, and belongs to the technical field of surface assembly. The method includes the steps that picture information of a PCB in the machining process is acquired from a database; a procedure with defects is determined according to the picture information; detection information of the procedure is acquired from the database; the detection information is analyzed, and the reason for the defects is acquired. The device comprises a first acquisition module, a determination module, a second acquisition module and an analysis module. Information of various machining devices can be collected, analyzed and utilized, quick positioning of the quality problem in the PCB machining process is achieved, the accuracy of PCB process quality monitoring is improved, corresponding treatment and control are conveniently conducted in time, and the PCB product quality can be effectively improved.