With the widespread application of giant magneto-resistance (GMR) sensor, it is urgently required to test its static and dynamic characteristic comprehensively. In this paper, the standard magnetic field generator based on the Helmholtz coils is designed to finish the comprehensive characteristic test of GMR sensor. Some GMR sensors are tested and compared by utilizing the standard magnetic field generator. The dynamic and static characteristic, angle characteristic and temperature drift characteristic are all compared. After that, in accordance with the insufficient during the testing course, the improving methods about angle characteristic testing, dynamic magnetic field generator and calibration platform are put forward. It will provide powerful support for improving the test quality of GMR sensor property.