Mg_0.33Zn_0.67Ofilm was prepared on silicon(100) substrate by RF magnetron sputtering (RFMS) method.Structure and optical properties of Mg_0.33Zn_0.67Ofilm were studied.Result indicates that Mg_0.33Zn_0.67O film deposited on Si substrate is hexagonal wurtzite structure.The growth orientation of the film is along c axis and the lattice of c axis orientation increases 0.03 nm.The film is present superior semiconductor property.The absorption peak of exciton is at 297 nm and the band gap of film is about 4.3 eV.The average grain diameter is about 20 nm.The fluorescent emission peak is at 368 nm under deep-ultraviolet excitation.