In this paper, a new concept named “Closed-loop Manufacturing System” (CLMS) is proposed. The Workpiece Machining Precision PID Control Model (WMPPCM) is outlined firstly, in which PID model expressions are structured and the role of proportion, integration, differential adjustment are analyzed. Then, the experimental method of WMPPCM is established to verify the feasibility and validity of this model. In the experiment, WMPPCM could be utilized to estimate the trend of processing error so as to conduct the adjustment before production. It is also proved that WMPPCM in CLMS has a significant effect on error compensation, which builds up the theoretical foundation for paper research on CLMS in terms of WMPPCM.