Based on GJB1801-1993 testing methods of major performance for test equipments of inertial technology, the design of high-precision rate calibration system based on MSP430 was proposed to achieve high-precision rate measurement and presented examples of the test. The system used the method of measuring angle in gate time, with the thermostat TCXO clock as a time reference, MCU controlled HCTL-2032 to decode count grating encoder output signal, while the design of the hardware periodic synchronization circuit ensured the equal measurement precision in different rate. Finally, computer application software made the data processed and display, store, print statements. The experimental results show that: at the ultra low speed standard device of Beijing Great Wall measurement and Testing Technology Research Institute, angular rate calibration results for rate ranged from 0.001 ° / s ~ 600 ° / s, the highest precision at 360 ° interval to reach 3 × 10-7.