Abstract: It analyzed the technological advantages of the proportional mixer which was applied in the foam fire-fighting process of coal mine. Combined with the practical situation of coal mine, it introduced the work principle and structure of the proportional mixer, calculated the main parameters, and carried out the experimental analysis for the proportional mixers of different types. The results showed that the proportional mixer made the foam fire-fighting preparation technology easier, the mixture ratio was more effective, and improved its security. The best water supply pressure for proportional mixer was from 0.8 to 1.0 MPa. It was also demonstrated that the different proportional mixer applied to the foaming agent with different foaming multiples.