The invention relates to a DEP flat plate type air filter. The DEP flat plate type air filter comprises a frame shell and parallel electrode assemblies. The frame shell is a rectangular frame. The parallel electrode assemblies are inlaid in the rectangular frame. Each parallel electrode assembly comprises a plurality of parallel dielectrophoresis electrodes, and the center distances or distances between the parallel dielectrophoresis electrodes are distributed uniformly. The dielectrophoresis electrodes are made of metal sections. The cross section of each metal section has protrusions which constitute ridges of each dielectrophoresis electrode. The ridges of the dielectrophoresis electrode of adjacent rows or adjacent columns are opposite. Every two dielectrophoresis electrodes with the opposite ridges are connected with one output end and the other output end of an AC power supply correspondingly. According to the DEP flat plate type air filter, the parallel electrode assemblies are adopted, different groups of electrodes can be connected to the two ends of the AC power supply correspondingly, and the dielectrophoresis effect can be formed within a large size range.