Diaphragm filter press has high pressing pressure and good corrosion resistance. The main difference between diaphragm filter press and ordinary chamber filter press is that two flexible membranes (composite rubber diaphragm is the whole membrane) are added on both sides of the filter plate, and during the operation process, when the feeding is finished, the high-pressure fluid medium can be injected into the diaphragm plate, and at that time the whole diaphragm will bulge and press the filter cake, so as to realise the further dewatering of the cake, which is the press filtration. Diaphragm filter press is used in sludge, sewage treatment, the lowest water content of the cake has been done below 60%, compared with the traditional chamber filter press, the highest solid rate of the cake can be increased by more than 2 times, and the cost of transporting the cake is greatly reduced, the diaphragm filter press is used in metallurgy, coal gas, papermaking, coking, pharmaceutical, food, brewing, fine chemical industry and other industries.