Abstract: The proton precession magnetometer is an instrument based on the proton precession frequency to measure the intensity of the geomagnetic field. According to the current development of the proton magnetometer at home and abroad, a new proton precession magnetometer control system based on the DSP28335 is designed, and the control circuit board and the key technology of the frequency measurement are discussed in detail. Unlike the traditional magnetometers based on the single chip microcomputer or PIC, the new design can solve the problems like the high cost, the limited functionality and the complex hardware circuit. A principle prototype is completed and the frequency measurement technique is tested in the laboratory. The results show that the measurement precision is up to an advanced level in our country.