Abstract: On the basis of 1:50000 regional geological survey in the Bogurda region of eastern Tianshan, the authors found monzonitic granite and diorite for the first time in Shijiezi and Caizigou area. Though U-Pb dating of monzonitic granite and diorite zircon by LA-ICP-MS technology, the authors obtained the fairly exact age data of 154.9±1.9 Ma and 152.7±1.8Ma, which suggest that the intrusion occurred in Late Jurassic. These are the first dating data for Mesozoic intermediate-acid intrusive rocks in Bogurda region. These data confirmed that the eastern part of Tianshan experienced magmatic activity in Late Jurassic. The results obtained by the authors provide new data for the event of the Mesozoic magmatism in the Junggar-Eastern Tianshan region, thus having great significance for studying tectonic magmatic evolution of the Eastern Tianshan region even the whole North Xinjiang.