To meet the demand of node-inner uniformity testing of multi-node infrared detector，a scan-testing system using infrared micro spot is developed，which consists of an imaging optical system for focusing spot infrared light source，an assistant vision aiming system，a precision six-freedom scanning platform and the data sampling and processing system.With high quality infrared light spot in micron，the developed system can achieve precise aiming between the micro infrared light spot and the sensor area of the detector and perform automatic testing of node-inner uniformity of the multi-node infrared detector.The real experiments conducted on some type detector shows that the system has high efficiency，good accuracy and stability.