Abstract: Single event upset (SEU) has always been an important factor affecting the reliability of spacecraft electronic equipment, which can cause anomalies in electronic equipment in orbit, and can result in serious spacecraft failure. In order to master signal event upset discriminating and positioning technology, and to study the mechanism between SEU physical position and particle energy, a technology method about SEU discriminating and positioning was proposed in this paper, and the principle prototype system was developed. The principle prototype system consists of silicon detector and electronics module. The silicon detector and the irradiation sensitive device are mounted in close proximity to each other in the vertical direction, and the position region where the particles are incident to the silicon detector corresponds to the physical position of the logical upset of the target device. On the one hand, the silicon detector is divided into an array grid, electronics module includes multiple detection channels, and high energy particles hitting a grid position of the silicon detector can be detected. On the other hand, the logical position of the target device where a single particle upset occurs can be detected by the circuit. Position sensitive detector is a silicon PIN type semiconductor particle detector dividing into a 4×4 array grid corresponding to each of the 16 measurement channels. Each grid is 4 5 mm wide square with a thickness of 300 μm. The silicon detector is packaged on a PCB board, where the detector grids are connected to the pads of the PCB by gold wire crimping. The electronics module mainly includes pre amplifier circuit, main amplifier and signal conditioning circuit, multichannel waveform signal peak seeking circuit, particle triggered circuit, SEU logic detection circuit for SRAM devices, FPGA control and communication circuit, etc. Waveform digitization technology is adopted, particle waveform peak value and particle arrival time are obtained through high speed analog to digital conversion and digital signal acquisition and processing. The basic method of SEU detection circuit for SRAM is the data read back comparison method, the FPGA writes a cyclically accumulating 8 bit number to the address range of the SRAM at the maximum rate of the SRAM read/write, then reads it out of the SRAM and compares it with the written data for the difference. If the result is “1”, it means that a SEU event has occurred; if “0” appears, it proves that no SEU has occurred. According to the results of laboratory test and single particle irradiation test, the LET of detectable energetic particle is greater than 6 06×10-3 MeV·cm2/mg, the position resolution of incident particles is better than 5 mm, the maximum count rate is more than 104 s-1, and the SEU inspection cycle time resolution of SRAM devices is 13 76 ms. By mastering the SEU discriminating and positioning of large capacity SRAM device and the radiation environment sensing capability, it can improve the performance of space electronics in orbit. By mastering the single particle flip screening and positioning of the large capacity SRAM devices and their radiation environment sensing capability, it can improve the on orbit performance of space electronics.