Abstract: The ion thruster magnetic field is one of the key factors that influence the plasma density in discharge chamber.The thrust wide range throttling can be realized by adjusting the magnetic field.To make clear the relationship between the magnetic field and the thrust，this paper builds the relative model between magnet current and the ion thruster thrust in theory first.On the basis of impact trend obtained by academic model，the thrust regulate experiment is designed and conducted，and then performance maps are formed.The thrust regulate experiment demonstrates that magnet current has influence on the ion thruster thrust indeed，and the relationship is nonlinear.