The invention relates to a separate-excited direct current motor soft starter based on XE164FN. The separate-excited direct current motor soft starter comprises a main circuit and a control circuit, wherein the main circuit uses an IGBT (insulated gate bipolar transistor) as a core, and a PWM (pulse width modulation) direct current chopping circuit is designed and forms an integral part for realizing the function of the system. The separate-excited direct current motor soft starter has the advantages that the soft starting of a direct current motor is realized, the requirements of good reliability, firmness and durability of the direct current motor under different environments are met, the smooth and impact-free starting of the direct current motor is realized, and multiple protecting functions are realized; a soft starting circuit mainly consists of a control circuit, a driving circuit and a PWM chopping circuit; the core of the control circuit is an XE164FN single chip microcomputer, the core part of the PWM circuit is the IGBT, the single chip microcomputer is used for generating triggering pulse according to a program instruction, the connection and disconnection of the IGBT are controlled by the driving circuit, then the voltage of an armature loop is controlled, and the average value of the armature voltage is gradually increased to the rated voltage, so as to realize the purpose of soft starting.