The yield of soluble whole-cell protein from Alicylobacillus acidoterrestris DSM 3922T cells is dependent on the effectiveness of cell lysis post fermentation. Various cell lysis approaches were investigated, including ultrasound, SDS, boiling, lysozyme, and cell lysis reagent treatment, and the different samples of soluble protein were determined by SDS protein polyacrylamide gel electrophoresis. The soluble whole-cell protein by one-factor-at-a-time experiments and response surface method was optimized. The results showed that the cell lysis reagent treatment was the most effective in extracting soluble whole-cell protein. The most significant processing parameters, namely incubation temperature, reaction time, and the ratio of cell lysis reagent volume and bacteria weight (A/B ratio), were optimized by using the Box-Behnken with a quadratic regression model built by response surface methodology (RSM). The influence order of factors to protein extraction rate was: A/B ratio, time and temperature. The highest soluble whole-cell protein yield at 161.18 mg/g was attained under optimal time, temperature, and A/B ratio at 37.4 min, 18.9℃, and 27.0 mL/g, respectively. The regression model of soluble whole-cell protein extraction was highly significant (R2=0.989 2), the experimental and simulated results were found to be in good agreement, which could be used to forecast.