A fixed cloth filter mainly comprises a storage tank which is with a filter cloth device and a backwashing device. The cloth filter device mainly comprises a plurality of parallel arranged rectangular filter cavity surrounded by the filter cloth, the bottom of the filter cavity is communicated with the bottom of the compensation tank on the side wall of the storage tank through a collecting pipe; The backwashing device mainly comprises a self-priming pump arranged outside the storage tank and a suction cup connected with the self-priming pump and arranged in the storage tank. The suction cup is arranged on the periphery of the filter cavity, and the center of the suction cup is connected with a power push rod arranged vertically.