SiOx films (x=1.3) are deposited on the silicon substrates by electron beam evaporation. The resistive switching behaviors from the device consisting of indium tin oxide (ITO)/SiOx/Si/Al with annealed SiOx layer as the resistive layer are investigated. It is found that on/off ratio of the device increases with the annealing temperature rising. The maximum on/off ratio reaches 109. The analyses of X-ray photoelectron spectrum and electron paramagnetic resonance spectrum reveal that the silicon dangling bonds in different valence states can be formed at different annealing temperatures, which is the main source of the conducting filament pathway. The result of ellipsometer indicates that the increase of refractive index of annealed SiOx film leads to the increase of the resistance of high resistance state.