Effective approach of collecting, transmitting, and handling complete product manufacturing information during machining process is necessary for realizing high efficiency manufacturing. In this paper, the architecture and implementation of closed-loop machining system (CLMS) is discussed and the method of realizing machining process control is introduced. An integrated information flow is built based on object-oriented description method to transfer complete product manufacturing information in CLMS. The functional and informational model of CLMS is established by using integration definition method. Online and real-time machining process control is implemented on an open STEP-NC controller which is collecting and analyzing information of machining process condition and inspection results during machining process. The software kernel of CNC controller implemented on a computer platform integrates with machine tool, sensors, and probe for real-time data collecting and online inspection. Finally, test parts are machined and inspected to verify the proposed machining process control method and open STEP-NC controller.