Abstract: The paper introduced a design scheme of intelligent protection device of magnetic starter based on W79E834,expounded design of hardware and software,implementation of protection function of the device.The device has protection functions such as short circuit,over-current,phase failure,earth leakage lockout and energy metering.The device has run in some coal mine and its result of field running showed that the device solves many problems existing in the simulation protection devices of coal mine,such as low precision,easy to fail and no energy metering,and so on,which realizes intellectualization and digitization of small flame-proof switch.