Abstract: Thrust changed in wide-range with high-accuracy,continuously adjustable and fast-response is the basis for spacecraft drag-free flight missions,it directly influences the success of the mission.Aiming at the application require-ment of gravitational gradiometry satellite and earth observation satellite for electric propulsion system with the ability of wide-range and continuous variable-thrust during orbit flight,the principle of realizing continuous variable-thrust of ion thruster was analyzed.And the essential ingredient in achieving thrust changed with wide-range,high-accuracy and contin-uously adjustable of ion thruster were researched.Based on it,thrust regulation tests and space environment adaptability and lifetime characteristic were conducted to reveal the engineering properties of 10 cm caliber continuous variable-thrust ion thruster.The thrust regulation rules over range 1 to 25 mN were obtained,and the thrust adjustment respowse with 50 μN resolution was realized.Above research will certainly provide technical support for drag-free flight missions of gravitational gradiometry satellite and earth observation satellite.