Abstract: 【Objective】 The purpose of the present study was to compare the quality of walnut and pecan varieties cultured in Yunnan and to establish a theoretical foundation for the deep processing of walnuts and pecans in Yunnan. 【Method】The main nutritional components of kernels from 40 representative varieties(divided into four groups based on the similarity analysis)were evaluated using a Soxhlet extraction apparatus, Kjeldahl apparatus, GC-MS and atomic absorption spectrometer. 【Reult】The crude fat content(mass fraction)of walnut and pecan varieties ranged from 52.11% to 71.77%, with the highest level observed in ‘Mississippi No. 10' in pecan variety No. 38. The varieties in Group Ⅰ and Group Ⅱ had greater advantages. Meanwhile, the Zn, Fe and Ca contents(mass fraction)ranged from 0.004 8 to 0.109 0 mg/g, from 0.009 8 to 0.192 8 mg/g, and from 0.254 8 to 0.651 7 mg/g, respectively. The kernels of the Group I varieties were rich in Zn and Fe, whereas those of the Group Ⅱ varieties were rich in Ca. The kernels of the Group Ⅰ varieties were also superior in regards to myristic, oleic and arachidic acid levels, whereas those of the Group Ⅱ varieties were superior in regards to lauric, palm, linoleic, linolenic and arachidonic acid levels; those of Group Ⅲ varieties were superior in regards to palm and stearic acid levels; and those of the Group Ⅳ varieties were superior in regards to behenic acid level. 【Conclusion】 Walnut and pecan are ideal source of edible oil. Varieties that have higher protein contents and lower oil contents can be used as protein beverages and peptides. The walnut varieties ‘Dali yangpao', ‘Jinhua' and pecan variety ‘Mississippi No. 10' are valuable sources of trace elements and can be used to develop Fe-, Zn-, and Ca-rich walnut protein or protein powders with nutrition and health functions.