Objectives: There is controversy in the formation time of the Yishake Group basalt on the north side of Kudi suture zone， Western Kunlun. Whether the basalt belongs to the ophiolite is controversial. Therefore, our research focuses on determining basaltic age and tectonic attribution. Methods:Based on the field work,through the mircroscope observation,the whole rock chemical analysis and the Zicon UPb isotopica analysis of the basalt. We determine basalt geochemical characteristics and isotopic age. Combined with ophiolite age and tectonic properties,we discuss basaltic formation and structural ownership. Results: Zircon LAICPMS UPb age of 519.5 ± 1.2 Ma is obtained from Yishake Group basalts, which indicates that the formation time. It shows that the Yishake Group basalt is an integral part of the Kudi ophiolite ,which Compares with the tectonic environment of the Kudi ophiolite and the age of formation. It is the product of the depletion of the Tethys ocean subduction. Yishake Group basalt shows that the age of the Kudi ophiolite is the Middle Cambrian—Late Cambrian，which Bases on the previous chronological data and the results of this paper。 Conclusions: Yishake Group basalts are part of the formation of the ophiolite formations for the Middle Cambrian. The Kudi ophiolites and the Yishake Group Group basalts are the products of the subtraction of the subduction.