Abstract: Using 24-bit resolution, high precision, wide dynamic range, delta-sigma A/D converter ADS1210 and CAN bus, a network data acquisition system for testing power supplies with high accuracy current is developed. Compared with the traditional digital voltage meter measuring system used in Beijing Electron-Positron Collider Upgrade(BEPCⅡ), this method is proved to be able to use in BEPCⅡ power supply system for measurement of current stability. The principle is analyzed and test data are presented.