Firstly introducing principle and technological process of PSA nitrogen-manufacturing system, on condition of its high air consumption and weak in nitrogen-manufacturing system at present. We repeatedly studied the controlled object in this process, analyzed the PLC procedure based on the program rule of PLC of Siemens S7-200 series, then re-program PLC procedure without altering the nitrogen production technique of PSA nitrogen-manufacturing system. At the same time, in order to improve the operation efficiency of the response of action, we also did experiment and demonstration in the consistency of the I/O port and peripheral equipment. In this paper, through optimization of hardware and software design, the nitrogen producing cost was calculated at RMB 0.35 per m3, declined by 12% from the original RMB 0.4 per m3.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.