In the practical production of cement, the semi-final grinding system of the cement roller press exhibits a lot of problems, including the untimely and inaccurate material flow adjustment, incapability of a side baffle to guarantee the saturated work of the roller press, the limited size of the ventilation section of the V-type powder separator, inconvenience in the adjustment of cold air valve of eddy current separator, as well as the low working efficiency of the system. With careful analyses, a new type of automatic control feeding mechanism is adopted, a V-type powder concentrator is designed and installed, the ventilation channels are increased, and the overall dumping procedure is employed. All these optimizations lead to an increase in the working efficiency of the roller press, which finally could reach up to 90%, with stable performance. The output of P·O 42.5 cement can be stabilized above 190t/h, and the power consumption of the process is actually reduced by 2.21kW·h/t.