Named by the patent applicant, the dual-flow rate water cap is a dual-flow rate water filter cap used in water treatment equipment. It consists of a water cap seat, a water cap cover, and a trapezoidal screen with ribs. Composed of tubes and guide tubes. The central axis of the trapezoidal screen tube is provided with a flow valve cup that is inverted and fixed on the water cap seat. The lower opening contains the upper part of the guide tube extending into the water cap seat. The bottom and wall of the flow valve cup and the guide tube are contained. The upper pipe wall is provided with multiple holes, and a flow valve core that can float up and down is provided on the top of the guide pipe. By setting the flow rate of the trapezoidal screen tube, the number of circular holes, the hole size and the gap distance, the water cap can meet various flow rate ratios of backwash and filtration water flow rates under different process conditions.