Based on geological field work, the authors studied mineral composition and chemical composition by using modern testing methods of observing microscopic sections and such means as EMPA, XRD, IR, XRF and ICP-MS. The results indicate that the Xiaosigou serpentine jade was formed through alteration of Mg-rich carbonate,and its main mineral is lizardite,and subordinate minerals include calcite, dolomite, diopside, phlogopite, magnetite, pyrite etc. REE of serpentine originated from marble and surrounding rock. The chondrite-normalized REE patterns of Xiaosigou serpentine jade are quite similar to those of sedimentary rocks, with steeply rightly-oblique shape, characterized by low REE amount, rich LREE and negative anomalies.