Abstract: The diamond film/silicon composite material for micro-strip gas chambers （MSGC） was obtained by HFCVD and related annealing technology. SEN images, Raman spectrum, and electrical properties were investigated. The results indicate that the roughness of the composite suhstrate is rather low, and the resistivity increases to 2. 9×10¹⁰Ω·cm after annealing treatment. The capacitance of the composite material is velT small and almost has no variation with frequency. All these prove that diamond film/silicon composite material is a promising substrate tor MSGC.