Abstract: To quickly find the causes of the accelerator unstable or lost beam caused by magnet power supply in Beijing Electron Positron Collider (BEPCⅡ) running, the rapid detection system for magnet power supply was developed. The stability of the system in 8 h is about 0.005%, and it can acquire over nearly 500 sets of magnet power supply current values most quickly in 0.33 ms. All data were written to the MySQL database in real time, so as to be able to quickly troubleshoot magnet power supply problem through historical data analysis and comparison.