In order to study and analyze the effect of different dates on qualities of walnut (Juglans siggillata L.), main qualities of wen 185, xin 2, zha 343 were determined and analyzed on September first, tenth, twentieth, thirtieth and October tenth 2014. The results showed that the contents of reducing sugar, fat and protein in wen 185, xin 2 and zha 343 increased and reached the peak on October tenth. The contents of Vitamin E and ash of walnuts were comparatively high, and less moisture was lost. Over all, there were significant differences between nutrients in every single specie, as well as three kinds of walnuts in different harvesting dates. The detection of qualities of three walnuts during different dates indicated that 30^th September was the best date for walnut harvesting.