Zircons in the garnet quartzite, staurolite-bearing garnet-biotite schist, amphibolite, and banded biotite plagiogneiss are dated by means of SHRIM n , and the shape and micro-texture of the zircons observed with CL and BSE. Ages of 2742 Ma, 2717 Ma, 2695 Ma, and 2642 - 2620 Ma are obtained in different micro-regions of the minerals. These ages are the age of the protolith of the Mengjiatun Formation, eruption age of tonalite, and age of the main metamorphic stage. The evolution of the Mengjiatun Formation is reconstructed. The most important result is the age of the protolith, which confines the sedimentation age of the Mengjiatun Formation. These results are significant in studying the Mengjiatun Formation, Taishan Group, and the geological evolution of western Shandong.