: A kind of method of directly control stepping motor is suggested in this article, in order to achieve control of variable speed, software of PLC pulse annular allocation and controlled pulse signal generator are designed. 提出了一种用PLC直接控制步进电机的方法,设计了PLC脉冲环形分配软件和可控脉冲信号发生器,用以控制步进电机的变速。