The invention relates to a system correction and magnetic interference compensation and fusion method for an airborne fluxgate magnetic gradient tensiometer. The method comprises the following steps: establishing an aircraft magnetic interference mode, establishing a single fluxgate error model, fusing the magnetic interference model and the fluxgate error model, establishing a magnetic gradient tensor component correction and compensation model, acquiring correction data from a uniform magnetic field area in the air, resolving a magnetic gradient tensor correction coefficient and inputting the measurement value and correction parameter of a three-axis fluxgate magnetic file into the magnetic gradient tensor component correction model, and calculating the corrected and compensated magnetic gradient tensor. The method provided by the invention has the advantages of completely covering the error factors of the airborne fluxgate magnetic gradient tensiometer and the aircraft magnetic interference type, expressing and solving in the correction model uniformly, realizing the solution of fusion of two problems of correction and compensation, and simultaneously completing the correction and compensation only by high-altitude correction and compensation flight. An iterative method is simple and practical, and a linear equation is solved by a least square method to ensure the correctness of the solution.