Abstract: In order to explore the best cadmium reduction process in parboiled rice during soaking,the present study focused on the effect of citric acid concentration,soaking temperature and time on the cadmium content during soaking.The test factors and the levels were selected based on the single factor experiments.According to the principle of the central combination test,the cadmium reduction process was optimized by using the 3-factor 3-level response surface method.The results showed that citric acid concentration,soaking time and soaking temperature had effect on the cadmium reduction rate during rice soaking,in which citric acid had extremely significant effect.The quadratic polynomial regression model was established and the response surface of the model and its contour were used to analyze the key factors and their interactions on the cadmium reduction rate.The optimum process parameters were as follows:soaking temperature 71℃,time 200 minutes and citric acid concentration 0.11 mol/L,under which the maximum cadmium reduction rate was 52.13%.