The invention relates to a device for measuring the accumulated water load resistance of a sun shade. The device consists of a test frame, a spray apparatus and a control system. The spray apparatus comprises a spraying pipe, a water supply pipeline and a water tank. Specifically, the water tank provides enough clean water for the entire test process, the water tank is located at the bottom of the test frame, and conveys water to the spraying pipe through the water supply pipeline. The test frame has a test piece fixation apparatus, the tested sun shade is unfolded and is fixed on the test frame through the test piece fixation apparatus, and the test piece fixation apparatus is located about the middle position in the longitudinal direction of the test frame, so that the spraying pipe can spray downward to the tested sun shade. The water supply pipeline is also internally provided with an electromagnetic flowmeter for measuring the spray water flow, a shielding valve for controlling adding of water to the pipeline, and a gate valve for adjusting the water flow.