The Xiangshan volcanic complex is located at the intersection of two fault systems: the first one, with northeast strike, is named the Yongfeng-Fuzhou fault and the other, with nearly north-south strike, is called the Yihuang-Ningdu fault. In this paper, the SHRIMP zircon U-Pb dating technique has been applied to the porphyritic dacite-rhyolite in the first event of Xiangshan volcanic complexes, and the authors obtain an 206Pb/238U age (136.6±2.7) Ma (MSWD=1.8). Then the authors can confirm that the eruption time of the porphyritic dacite-rhyolite should be about 136.6 Ma. Combined with the former reported ages, it seems more reasonable that the actual ages of the porphyroclastic rhyolite lavas should be a little younger than that formerly reported.