The utility model relates to a filter capable of alleviating the blockage of a filter screen. The filter comprises a filter shell, a liquid inlet, an liquid outlet, a residue collecting chamber, a drain outlet, a filter screen and a high-pressure washing spray nozzle, wherein the liquid inlet and the liquid outlet are formed in two sides of the filter shell and is positioned in the same axis; the residue collecting chamber and the drain outlet are formed below the filter shell; the filter screen is arranged in front of the liquid outlet; the high-pressure washing spray nozzle matched with the filter screen in shape is arranged on the outer side of the filter screen. The filter is characterized in that a dispersing device which can be used for dispersing liquid at an inlet of the filter is arranged between the inlet of the filter and the filter screen, so that the flow velocity of the liquid is reduced, the contact area between the liquid and the filter screen is increased, and the phenomenon that the filter screen is locally blocked as the liquid directly impacts the filter screen is avoided.