This paper reported a combined internal and wholerock SmNd isochron age, and Nd and Sr isotopic data for gabbro of the Shemalagou ophiolite in north Tibet . The SmNd isochron of data for two whole rocks and garnet and hornblende se parates from the rocks yields an early Jurassic age of 191(22 Ma, which inosculat es with the geological facts that there are Jurassic Radiolarian fossils found in the abysmal cherts which was nipped between the pillow lava and volcanic clastic sediments. it suggests the SmNd isochron age of 191±22Ma(SmNd) is reliable and stand for the formation of Shemalagou ophiolite during the early Jurassic. εNd（t） values ranges from +7.0 to +5.4, indicating that gabbro was formed in oceanic islandarc setting. Comparing with the Yaluzangbu ophiolite which located in south Tibet, Shemalagou ophiolite samples has lowerεNd（t） and reflects t heir difference on geological setting. Strontium initial ratios (87Sr/86Sr)i of three whole rock samples of Shemalagou ophiolite separately are 0.7059，0.7061 and 0.7045 with an average of 0.7055. They are higher than modern times abysmal lava (0.7020~0.7035). Nd, Sr isotope characteristics suggests Shemalagou ophiolite was formed under the behindarc basin outstretched，which developed during the early Jurassic. Magma source may has ever got some mixing of diving ocean crust or ocean sediments.