The invention discloses a spray test device and a spray test method for a containment vessel. The spray test device comprises a containment vessel simulation body, a spraying system, a water storage tank and an air supply system, wherein the spraying system is used for spraying cooling water into the containment vessel simulation body, the water storage tank is used for supplying the cooling water to the spraying system, and the air supply system is used for simulating the internal state of the containment vessel and supplying an air source for the containment vessel simulation body; the spraying system is connected between the containment vessel simulation body and the water storage tank, and the air supply system is connected with the containment vessel simulation body; and a temperature measurement point and a pressure measurement point which are respectively used for measuring the internal temperature and pressure of the containment vessel simulation body are arranged on the containment vessel simulation body. According to the spray test device and method, containment vessels of different reactor types can be simulated; and a spray test is carried out by virtue of the spraying system to evaluate the cooling and decompression performance of the spraying system, so that the spraying system applicable to the corresponding containment vessel can be obtained.