Using orthogonally rotational combination design, alkali extraction and acid precipitation was proposed for extraction of protein from walnut dregs.The optimal preparation conditions of the protein were as follows: extracting pH 9.0, extracting time 124 min, extracting temperature 53 ℃ and solid-liquid ratio 1∶22 (m∶V). Under the conditions, the yield of protein was (67.94±005)%, and its isoelectric point was pH 5.0 .