Shanxin granite intrusion is located in the Majizhang area, Le'an, Central Jiangxi Province, where Mo W Sn poly metallic mineralization occurs. Through precise LA ICP MS U Pb dating of zircon from Shanxin fine two mica alkali feldspar granite, the crystallization age of the intrusion was determined to be 152.5±1.3Ma, corresponding to Late Jurassic era. The results of mineral chemistry indicate that micas are muscovite and ferrimuscovite, feldspars are albite and orthoclase. The and feladspars are all alkali feldspar. The granties are characterized by high in silicon, Na2O+K2O aluminum, low in calcium and magnesium, slightly to strongly peraluminous. The granites also show strong depletion of Sr, Ba, Ti, P and Eu, enrichment of Rb, Th, Ta and LREE, high Ga/Al and strong negative Eu anomaly. The chondrite normalized patterns of rare earth elements are in seagull forms. The characteristics of the Shanxin granite are similar to that of aluminous A type granite of the Nanling area. The Shanxin fine granited granite is of A type. The characteristics of high Rb/Sr and Rb/Ba ratios, low Nb/Ta, Zr/Hf and K/Rb ratios indicate that the magma experienced a strong fractional crystallization process and fluid process. Its εNd(t) value is -8.9 and the calculated two stage modle age of Nd isotope is 1662Ma, suggesting that the magma derived from the partial melting of old continental crust rocks. Combined with the previous research results, the granites of Shanxin unit might form in post orogenic tectonic environment that is the transition from collision orogenic to intraplate extension. The development of abundant faults and felsic dykes and the W bearing granite suggest that there may be a large concealed rock which might have good potential for tungsten—tin mineralization.