A dilution filter apparatus, comprising: a sampling component, a top cover and a sample tube, whereby the sampling component is assembled on the top cover; whereby the sampling component assembled on the top cover is placed in the sample tube, and the top cover is sleeved on a top end of the sample tube causing the top cover and the sample tube to be in threaded fastening connection and the sample tube is sleeved outside the sampling component; whereby a through hole is formed in the center position of the top cover; whereby the sampling component comprises a connecting cylinder and a sampling part, the sampling part is concentrically connected with the connecting cylinder; whereby the sampling part is configured for collecting suspension; characterized in that: the connecting cylinder of the sampling component is concentrically and rotatably connected with the top cover, so that the connecting cylinder, after being mounted, can freely rotate around a common axis of the connecting cylinder and the through hole of the top cover, and can drive the sampling part to rotate to stir suspension; whereby the sampling part further comprises a suspension collecting chamber and a plurality of suspension collecting windows communicated with the suspension collecting chamber; whereby two suspension collecting windows are arranged at two opposite walls of the suspension collecting chamber respectively, each suspension collecting window is provided with a filter net and the filter nets arranged on different suspension collecting windows are different in aperture; whereby the sampling part is provided with a plate extending out in a vertical direction to a plane where the filter net is located for each of the filter nets, the plate extending out is configured to prevent the suspension from directly impacting the filter nets to cause blockage. a sampling component, a top cover and a sample tube, whereby the sampling component is assembled on the top cover; whereby the sampling component assembled on the top cover is placed in the sample tube, and the top cover is sleeved on a top end of the sample tube causing the top cover and the sample tube to be in threaded fastening connection and the sample tube is sleeved outside the sampling component; whereby a through hole is formed in the center position of the top cover; whereby the sampling component comprises a connecting cylinder and a sampling part, the sampling part is concentrically connected with the connecting cylinder; whereby the sampling part is configured for collecting suspension; the connecting cylinder of the sampling component is concentrically and rotatably connected with the top cover, so that the connecting cylinder, after being mounted, can freely rotate around a common axis of the connecting cylinder and the through hole of the top cover, and can drive the sampling part to rotate to stir suspension; whereby the sampling part further comprises a suspension collecting chamber and a plurality of suspension collecting windows communicated with the suspension collecting chamber; whereby two suspension collecting windows are arranged at two opposite walls of the suspension collecting chamber respectively, each suspension collecting window is provided with a filter net and the filter nets arranged on different suspension collecting windows are different in aperture; whereby the sampling part is provided with a plate extending out in a vertical direction to a plane where the filter net is located for each of the filter nets, the plate extending out is configured to prevent the suspension from directly impacting the filter nets to cause blockage.