Muong Lat granitoid complex located in Thanh Hoa province. It is composed of two mica granite, aplite and pegmatoid. Rock forming minerals include mainly K-feldspar, quartz biotite and muscovite. Crystallization age of pegmatite in Muong Lat body is determined by U-Pb zircon LA-ICP-MS method. Most of the analytical results 206Pb age / 238U ranged from 217–238 Ma, average 230 ± 7 Ma. Age results indicate, the existence magma activity in the study area. Three inherited zircon core gaves age of ~2.8Ga, ~2.4Ga, ~1.8Ga, ~400Ma and ~750 Ma, suggesting that the continental crust of the study area including material composition of the Neoarchean, Paleoproterozoic, Paleozoic and Neoproterozoic