A large new serpentine jade deposit was found in Ji'an area, Tonghua City, Jilin Province. The results of X-ray fluorescence spectrometry show that the content of SiO₂ is from 35.21% to 37.18% in weight percentage, MgO from 46.94% to 49.72%,, the ratio of FeO/Fe₂O₃ is in the range of 0.174~0.685, respectively. The analyses of XRD indicate that there are characteristic peaks at 0.733 nm, 0.366 nm, 0.250 nm, which are attributed to lizardite. The main mineral of the serpentine jade is lizarite, commonly with forsterite. The characteristic XRD peaks of frosterite, dolomite, brucite also occur in the X-ray diffraction spectra. The IR spectra of 3 650~3 700 cm, 950~1 100 cm, 400~700 cm^-1 are found in the serpentine. The Ji'an serpentine jade deposit was formed by regional metamorphism,, lizardite was the product of forsterite hydrothermal alteration under the low temperature condition.