Derivation of unknown parameters or deviation of practical aspheric optic surface equation with surface error are in practical demand for aspheric machining accuracy analysis, optical system imaging quality analysis, and decomposition analysis of optical lenses. Beginning with an analysis of the data format obtained from Taylor Hobson Talysurf, the key technique used for inversion method to derive aspheric equation based on genetic algorithm and measured data is analyzed. Programmable inversion of aspheric equation is given. It is shown that the method proposed is practical.