Objectives：The Hasashan ophiolite is located in the middle of suture belt in central East Kunlun，which is one of the three core geological relics of the Mt. Kunlun UNESCO Global Geopark, The combination of ophiolite is relatively complete, but the times and tectonic attributes of the ophiolite in this area are still controversial, and lack of dating data, which leads to various understandings of the tectonic setting and evolution history of the region.Methods：On the basis of detailed field geological surveys and microscopic observations,we chose to collect fresh gabbro samples from the ophiolite in Hasashan for zircon UPb isotopic age analysis. And systematically collected fresh ophiolite components for Petrogeochemical analysis. this paper combines the occurrence of the zircon UPb age and the main trace elements in the field to investigate the formation age and tectonic setting of the ophiolite. This study provides basic geological data for identifying the Kunlun Suture Zone and studying on the formation and evolution of the East Kunlun Orogenic Belt .Results：The LA-ICP-MS zircon U-Pb dating of the gabbro in cumulate ophiolite shows that the age is 438.5 ± 2.6 Ma, which indicates that the ophiolite was formed in the Early Silurian；Detailed petrogeochemical studies show that the protolith of serpentines is peridotite and the total amount of rare earth elements of serpentine is lower, with a right oblique distribution curve. Gabbro showed that the light rare earth has a higher concentration of heavy rare earth with varying degrees of Eu anomalies. The distribution curve is more gentle with slightly to the right. The light rare earth of basalt is relatively higher than heavy rare earth. And it shows systematic enrichment of LILE, there are obvious Eu negative anomalies, no differences of HFSE and slight depletion of Nb and P. Each sample distribution curve is roughly parallel to the EMORB line, which suggests that the magma is homologous magma. It has features of EMORB and the midocean ridge transition to the island；the formation of the tectonic environment should be the initial small ocean basin environment, may be the original ProtoTethys Ocean crust, formed in the early stage of the land conversion.