The Luzhenguan Group is an important part of the North Huaiyang low grade metamorphic belt (NH), whose evolution process is critical for offering evidences for deep subduction of the ultra pressure rocks and getting integrated history of the Dabie Mountains. In this work, some biotite two feldspar gneisses with garnet and garnet—biotite gneisses were collected in Niujiaochong and Yu’erjie, Huoshan County, for electronic analysis. Using the garnet—biotite—plagioclase—quartz geobarometry, metamorphic pressure between 1.89~1.99 GPa and the average 1.94 GPa was gained. Based on average density of the rocks located in upper and middle crust of the Dabie Mountains, a conclusion is drawn that the Luzhenguan Group once subducted into 64.7 km in depth. This conclusion suggests that the North Huaiyang belt experienced deeper subduction and supports that the suture zone between the North China block and the South China locates in north of the North Huaiyang belt.