Abstract: The key factors affecting ocean evaporation duct inversion from radar sea clutter are analyzed, and a dual-parameter modified refractivity profile for evaporation duct is modeled. A method for improving the inversion precision is introduced. Because the sea clutters from different antenna heights carry different duct information, the improved inversion model for evaporation duct is constructed using radar clutters from changeable antenna heights, with the antenna servo system employed. Through duct inversion comparisons with the case of fixed antenna height, the high inversion stability and precision of this model are confirmed.