User package program run on PC was developed for clinical spirometric test, which enabled to perform popular FVC, SVC, and MVV test items in a very convenient manner. In addition, a program module for research was implemented to study breathing pattern of a patient. The program written in C language was designed to run on Windows OS, and consisted of patient information management, test procedure control, results print out, and accumulation of parameter values in a customized data base which made possible future clinical research and quality assurance. When engaged with the previously developed respiratory air flow measurement unit, the system resulted in an accurate enough performance in that FVC data showed a high correlation coefficient of higher than 0.98 with an imported system. The technician tried the present system under clinical environment and judged the convenient utility to be satisfactory. Therefore, industrialization effort is being currently made and expected to be successful.