The invention relates to the technical field of sewage treatment, and discloses a sewage precipitation system. The sewage precipitation system comprises a precipitation tank body, a water inlet pipe, a flow resisting channel, a flow resisting plate, a drain pipe, a baffle plate, a scum fishing mechanism and a blow-off pipe, wherein the scum fishing mechanism comprises a pumping part, a conveying part, a water receiving groove and a flow guide pipe. In the embodiment of the invention, the scum fishing mechanism is arranged in the sewage precipitation system, so that scum on the water surface of a precipitation cavity can be fished and conveyed out of the precipitation tank body, and the scum in the precipitation cavity is prevented from flowing towards the drain pipe.