与传统的摄影调焦系统相比较，针对焦距可以灵活调整的要求，提出了基于TMS320F240 控制步进电机调焦的设计方案，利用F240 控制电机驱动器UP-4HB03M 按照计算所得的调焦轨迹进行调焦。实验结果表明，本系统调焦曲线与理想曲线拟合度较好，拍摄已知运动轨迹的目标，达到了满意效果。关键词：TMS320F240；步进电机控制器；步进电机ABSTRACT: Some traditional adjustment of focus photography systems are compared.According to the requirement of flexible adjustment, a scheme of adjusting focus based onTMS320F240 by controlling step motor is presented. The focus is adjusted according to the curve, which has been calculated already. Finally the result given by experiment shows that the curve of adjusting focus is fit well with the ideal curve. Shooting the goal of the known movement orbit has reached the satisfactory result.Key Words: TMS320F240; step motor control; step motor