This paper proposes a flexible gear lead modification and precision control method based on multi-axis linkage. To solve the problem of monotonicity of modification curve in gear lead modification technology. Firstly, establish the lead modification tooth surface model and the continuous generating grinding trajectory planning model of the arbitrary lead modification gear, Superimpose the corresponding axis additional motion amounts are calculated according to the tooth surface modification amounts on the standard grinding motion locus of the grinding wheel, gear lead modification through multi-axis linkage. Secondly, according to the principle of the continuously developing method and the positional relationship between the worm wheel and workpiece gear during the machining process, establish an accuracy prediction model for workpiece tooth profile deviation, pitch deviation and helix deviation based on electronic gearbox. Finally, building an experimental platform, conducted experiments on gear lead modification grinding and gear accuracy prediction experiments, verify the correctness of the proposed flexible gear lead modification and precision control method. This method provides a new low-cost, high-flexible and high-precision method for the machining of gear lead modification,