Abstract: The diaphragm filter press currently used is technically backward and low in efficiency and its cake product has a high moisture. To tackle the problems, an industrial high-pressure diaphragm filter press is introduced by the plant to conduct test on influence on cake moisture produced by each working parameter and the optimum working conditions, with an aim to explore the feasibility of using this kind of filter press in place of the existing one. Study result shows that a best result can be expected when the filter press operates with the following parameters: extrusion pressure—6 MPa, extrusion time—550 s, feed pressure—1.5 MPa, feed concentration—20% and feeding time—900 s; and through application of the technically upgraded cake discharge and filtrate treatment processes developed by the manufacturer for the existing filter press, the high-pressure type can work with a far better performance than the existing one.