Objective This study designed one test system for blood oxygen saturation (SpO2) to help the undergraduates majoring in medical equipment to understand the operational principle and structures of SpO2 test equipment, be familiar with medical equipment design procedures, and obtain real-time data as well as visual displayed original SpO2 curve and values in experiments. Methods VC++ 6.0 ActiveX and the communication between control module MScomm and SpO2 test module were used to design the system. This software interface could control the SpO2 test module start up, data collect, data upload, parameter transform and turn off quickly. Results This convenient system could make real-time collection of original data in EXCEL and text format, visual display, which might check SpO2 and provide the raw data for researchers. The test results of this oxygen saturation system were similar to those of other test equipments. Conclusions This proposed system is open, programmable, extensional in function and can be used in curricular experiment and extra-curricular research by undergraduates of medical equipment.