In order to explore the best extraction conditions of Defatted Antarctic Krill Protein (DKP) and increase the added value of defatted Antarctic krill powder. Using defatted Antarctic krill powder as the raw material, and the protein was extracted by alkali solution and acid precipitation. Taking the protein yield as the index, the single factor test was carried out on the four influencing factors of extraction temperature, extraction time, solid-liquid ratio and NaOH concentration. The extraction process was analyzed and optimized by response surface methodology. The actual optimum extraction conditions of DKP were optimized by response surface methodology as follows: extraction temperature 69 ℃, extraction time 65 min, solid-liquid ratio 1:15, NaOH concentration 2.2%. Through validation test, the actual protein yield was 31.93% ± 0.35%, with a relative error of 1.19%±1.01% from the theoretical value of 32.32%.  The results show that the regression model is accurate and can be used to guide the production practice, which is beneficial to improve the added value of the defatted Antarctic krill powder and promote the sustainable development of the Antarctic krill industry.