The invention relates to a semi-digitalization direct current stator variable voltage speed control system, which comprises a main controller, a speed setting device, a power module, a current transformation device, a motor, a reel and a processor which is used to adjust parameters, wherein the process is used to adjust the parameters, receives a plurality of input signals which pass through analog to digital conversion, and outputs the signals after comparison processing adjustment, the system also comprises a D/A conversion module which is connected with an output end of the process, is used to convert a part of digital signals which are output by the processer into analog control signals, and outputs the analog control signals to the main controller, wherein the main controller controls the motor to operate according to the analog control signals. The system of the invention realizes parameter arrangement and adjustment through increasing the processer and has the advantages of high adjusting precision, stable working performance and strong anti-interference ability. The system only needs to input parameters of an original device into a new device in in-situ device replacement. The maintenance quantity is reduced and the safe production has more reliable guarantee. The electronic over-speed and hook gliding preventing protection is increased, and the system safety is increased.