Abstract: The magnetic cleanliness of satellites is one of the key factors affecting the precision of space magnetic field measurement. In order to estimate the magnetic cleanliness of Zhangheng-1 satellite in the design stage, a magnetic modeling and simulation method based on a single-machine multiple magnetic dipole model was proposed. First, a single-machine multiple magnetic diple model was constructed using its magnetic field measurement data. Then the whole satellite magnetic model was formed with a combination of the installation positions and directions of single-machines. In the end the magnetic field at the absolute magnetic field calibration device of the satellite was calculated. The results of the whole satellite magnetic experiment show that the simulation method is reliable and effective. This method may be applied to the magnetic modeling and simulation of similar high magnetic cleanliness satellites.