The invention discloses a device for a slope protection dike damage test under wave loads and a method, and belongs to the field of sea wall slope damage. The device comprises a simulation box and a top cover, wherein the simulation box is used for containing a building model and comprises an upstream part, the building model, a downstream part and a vertical loading part, the upstream part and the downstream part simulate different water levels, the upstream part comprises a wave maker and a wave height meter, the wave maker is used for pushing water flow of the upstream part to form waves, and the wave height meter records the height change of the waves; the upper part of the building model is open, horizontal vibration devices are mounted on a left side plate and a right side plate of a wooden box, the vertical loading device can move along a main beam, and the top cover is provided with a humidifier, a hygrothermograph and a heating tape, and covers the top of the simulation box to form a closed space. The device can be used for researching the influence of the wave loads, the earthquake loads and the overload on the damage rule of a slope protection dike under different temperatures and humidities, and has application prospects in the aspect of exploring the damage of the slope protection dike under the wave load condition.