The invention provides a processing method for sugar slag generated in wet-method sugar preparation. The method comprises the following steps: evenly mixing gluten water and sugar slag obtained in the wet-method sugar preparation, carrying out filter pressing, and drying the filtering slag to obtain an endosperm protein product. The invention provides the endosperm protein product obtained according to the above method. The invention provides a wet-method sugar preparation method, which comprises the following steps: preparing raw starch milk by using starchiness raw materials; carrying out centrifugal separation on the raw starch milk to obtain refine starch milk and gluten water; successively liquefying and saccharifying the refine starch milk; and carrying out filter pressing on the saccharified product to obtain sugar liquid and sugar slag. The invention is characterized in that the processing method is adopted to process the sugar slag and the gluten water. according to the method disclosed by the invention, the sugar slag generated in the wet-method sugar preparation can be successfully mixed with and the endosperm protein, therefore the obtained endosperm protein product has light color and hardly self-ignite. Compared with the prior art in which the sugar slag and the gluten water are not mixed, the method has the advantage that the yield of the endosperm protein product can be improved so as to further improve the economic benefit of the wet-method sugar preparation.