Traditional Direct Current Speed Control System is designed mainly by adopting engineering method and is widely used in practice. In this paper, a new approach is proposed for the design of this kind of control system based on the combination of classic design method and modern control theory, and it can avoid the problems occurred in engineering method, in which the closed-loop poles cannot be randomly configured. Firstly, the system is designed on modern control theory and then implemented through classic method of equivalent transformation of structure. Secondly, simulation is done in matlab/simulink from the data obtained. Finally, disturbance resistance emulation is carried out respectively through traditional method and the method in this paper, which demonstrates the effectiveness of this method.