Abstract: The continuous variable-thrust ion thruster is the key to realize compensation of the non-gravity dumping at high continuum speed with high accuracy for gravitational gradiometry satellites, and its performance directly influence the success of the satellite engineering mission. Aiming at the application requirement of drag-free mission of gravity gradient measurement satellite for 10 cm continuous variable-thrust ion thruster, the influence of magnetic induction intensity on wide range and continuous variable-thrust of ion thruster is analyzed. On this basis, the changing rule of the output thrust of the ion thruster was studied when the magnetic flux density was adjusted in the discharge chamber with different anode gas flow rate. The relationship between the magnetic flux density and the discharge voltage, the propellant utilization efficiency and the ion production cost of the thruster was obtained. The mapping relationship between the magnetic flux density and the flatness of ion beam was obtained by using Faraday probe device. The results showed that the output thrust of 10 cm continuous variable-thrust ion thruster increases with the increase of magnetic flux density, and the relationship between discharge voltage and magnetic flux density presents a nonlinear quadratic polynomial relationship. With the increase of magnetic flux density within a certain range, the propellant utilization efficiency increases, the ion production cost decreases gradually, and the flatness of ion beam increases correspondingly. However, if the magnetic flux density is too large, the performance of discharge chamber changes unexpectedly, and the plasma becomes unstable. The research will certainly provide technical support for the construction of the thrust control algorithm of the 10 cm continuous variable-thrust ion electric propulsion system and the magnetic circuit optimization of the thruster.