The Simianshan garnet-bearing migmatitic granite, which is located at the northern foot of the Dabie Mountain, is mainly composed of monzonitic granitoids. In this paper, the petrological and geochemical characteristics of the granitoid were studied to constrain the petrogenesis. The result shows that these granites are rich in silica, with high content of alkali (Na₂O+K₂O). Overall, they are metaluminous to peraluminous granites and belong to the high-K calc-alkaline series, with locally inhomogeneous migmatization. The granitoids are characterized by enrichment of Ba, Th, K and depletion of Nb, Sr, P, Ti. The abundance of ΣREE varies in the range of 115.05×10^-6~430.85×10^-6. Their LREE is enriched compared with HREE and the δEu values fail to show obvious abnormal phenomena. The preliminary results of this study show that the granitic magma was derived from the partial melting of mid-lower crust, which was triggered by delamination or underplating.