Abstract: In fusion experiments, the integrator is a fundamental method to recover differential signals. Developing a longtime low-drift integrator system is very important for the Tokamak experiments. Based on the differential integrator, combining linear isolation technology, remote control programmable amplifier technology and embedded Ethernet communication technology, the integrator system on the Experiment Advance Superconductor Tokamak (EAST) was designed. A kind of global calibration method was presented, and it improved the accuracy of the integrator system. The test results show that, when the gain is 1, the integration drift is less than 10 mV within 100 s, which meets current demand of the EAST experiments. The integrator system has been used in the experiment on the EAST, and achieved good operating results.