Abstract: The China Spallation Neutron Source (CSNS) accelerator mainly consists of a linear accelerator, a 1.6 GeV rapid cycling synchrotron (RCS), a low energy transport line and a high energy transport line. A rotating coil measurement system was developed for the DC magnets of the CSNS accelerator. This system solves the compatibility problems of different center heights, masses, effective lengths, and magnetic field strengths among CSNS bulk magnets. After testing, the repeatability error of the integral field measurement is less than ±0.02%, the repeatability error of harmonics is less than 0.005%, the repeatability error of the magnetic center measurement is less than ±0.03mm. It has successfully completed the task of detecting 150 magnets of the China Spallation Neutron Source. In this paper, the development plan, function, accuracy, types of measured magnets and some measurement results are introduced.