Abstract: Aiming at the existed problem of current impact when three-phase asynchronous motor(adopted) method of step-down starting,the paper proposed a design scheme of new type of soft starter of three-phase asynchronous motor,introduced design of hardware and software of the soft starter in details.The soft starter used 80C196KC single-chip microcomputer and power and electronic technology to adjust input voltage of motor automatically and had advantages of simple structure,easy to adjust parameters,as well as smooth to start motor.The experiment result showed that the soft starter could complete soft starting of motor by setting different starting voltage and starting time according to demands.