Cu3N thin films can potentially be used for development of optical storage devices and integrate circuit of semiconductor. In this study the Cu3N films were deposited on glass substrate successfully by reactive direct current magnetron sputtering at different N2/(N2+Ar) flow ratio. The results showed that the nitrogen partial pressure affected the preferring orientation of the thin films when the sputtering power and substrate temperature was fixed. With increasing N2/(N2+Ar) flow ratio from 10% to 90%, Cu3N(111) orientation with rich-copper changed to Cu3N(100) orientation with rich nitrogen, the transmittance of the thin films improved gradually, and the corresponding optical band gap (Eg) increased from 1.10 eV to 1.21eV. The resistivity of copper nitrogen films changed from 5.62Ω.cm to 3.00×103Ω.cm at the scope of 10%~90% of N2/(N2+Ar) flow ratio.