There are mainly felsic granulites in Tongbai area located at southern fringe of the North China plates. A study of the mineral chemistry and the features of the mineral paragenesis and the calculation with thermobarometers revealed that the granulites in Tongbai area were formed under thep-tconditions of 700~840℃and 0.61~0.85 GPa, belonging to typical medium-pressure type, and the geothermal gradient is approximately from 28 to 31℃/km. The granulite facies metamorphism probably occurred at the late stage of Early Palaeozoic.