Low solubility and high cadmium content are the technical bottlenecks of protein resource utilization in rice dregs by-products. Rice dregs with high cadmium content were used as raw materials,Alcalase 2.4 L alkaline protease was selected, The factors of enzymatic hydrolysis of rice dregs were studied by response surface center combinational design. According to the results of single-factor experiment, the time of enzymatic hydrolysis, pH, the amount of enzyme added and the concentration of substrate were taken as the influencing factors, and the soluble nitrogen recovery rate of rice dregs protein was taken as the response value. The optimal conditions for enzymatic hydrolysis were obtained by analyzing the experimental results with the assistance software Design Expert 8.0 and were as followed temperature 60 ℃, enzyme content 1.25%, pH 8.0, substrate concentration 7.5%. Under the condition the rice dregs protein soluble nitrogen recovery rate reached 49.68%. Under the conditon the cadmium content in insoluble enzymatic precipitation was 7.71 mg/kg, which increased by 54.5% by comparing with rice dregs protein. The cadmium content of soluble enzymatic hydrolysis supernatant was 1.43 mg/kg, 71.3% lower than that of rice dregs protein. It was proved that the protease could not only degrade the rice dregs protein into small peptides but also dissociate cadmium from the rice dregs protein.