We report a discovery of Kulule granites in the middle Tianshuihai Massif. Zircons separated from this granite is dated to be 500.7±1.1 ~498.7±1.4Ma by LA-ICP-MS. The granites are lack of amphibole and muscovite, with geochemical features of high SiO2(73.49%~77.47%), middlehigh K2O(1.88%~4.14%) and low P2O5(0.02%~0.05%),which are similar to the typical metaluminous to weakly peraluminous Itype granites with high differentiation. Additionally, the granites have high total REE concentrations (66.81×10-6~135.43×10-6), high (La/Yb)Nvalues (3.86~7.98) and (La/Sm)Nvalues (3.46~4.22), strongly negative Eu anomalies (δEu =0.35~0.66),which display the enrichments of Rb,Th,U and K and the depletions of Nb,Ta,P,Ti and Sr. Microgranular mafic enclaves (MMEs) are common in the plutions and combined with the discrimination diagrams of diagenetic process, which implies the formation of Kulule granites has a mantle source and significant magma mixing. Based on the regional research, Kulule granites might be formed in an magmatic arc tectonic environment during the Proto Tethys southward subduction, which suggestsa bidirectional subductionof the Proto Tethys Ocean in the Early Paleozoic era.