The invention relates to a high-precision radiation-resistant microsatellite three-axis magnetorquer which comprises two magnetic rods provided with metal cores, a hollow magnetorquer body, a processor and magnetometers. The two magnetic rods provided with the metal cores form an X-axis magnetic rod and a Y-axis magnetic rod respectively and are wound by coils, the hollow magnetorquer body forms a Z-axis hollow coil, the X-axis magnetic rod, the Y-axis magnetic rod, the Z-axis hollow coil, the processor and the magnetometers are integrated into a PCB and form modularization, and three execution mechanisms are independently driven by PWM signals. The invention further relates to a work method of the high-precision radiation-resistant microsatellite three-axis magnetorquer. The high-precision radiation-resistant microsatellite three-axis magnetorquer and the work method thereof have the advantages that reliability of the magnetorquer is improved, and control precision of the magnetorquer is improved; the functions of current monitoring and temperature measuring are achieved, the magnetic rods and a fastening piece are integrally designed, the magnetorquer is convenient to assemble, and strength is increased.