This study compared the main compositions of the different areas walnuts. A large diversity was found in moisture, ash, total fat and crude protein content. We got four kinds of walnuts from different areas of northeast China (A: Suifenhe Heilongjiang B: Yichun Heilongjiang C: Mudanjiang Heilongjiang D: Baishan Jilin). The sample D has the most moisture compared the others, 6.563%. The ash and total fat contents of the sample C are more than others, respectively 2.96% and 56.42%. For the crude protein, the kind from sample A is the most, 34.349%. The experiment also studied the protein extraction of the degreased kernel by distilled water. During the extracting process, three main factors including ratio of solid to liquid, exacting time and temperature were studied by using single factor analysis method. According to orthogonal test results, when the solid-liquid ratio, time and temperature were respectively 1/45, 3.5h, 45°C, the material (WKCD) had the highest protein extraction ratio 57.62%.