Aiming at the parfocalization feafures of large zoom ratio infrared continuous zoom lens，the bi-directional compensation curve of zoom lens is fitted by using specific data structure and on-line calibration method. By changing the ambient temperature and double-line interpolation method，the fitting curve is expanded into a two-dimensional network table and stored in FLASH. Parfocalization feafures compensation based on pre-processing algorithm，double-loop control algorithm and pulse control algorithm can quickly and accurately realize compensation motor drive control. At the same time，the problem of insufficient compensation when the target distance is less than the minimum imaging distance can be effectively compensated by adding gray gradient calibration.