The effects of different aid-gases and technological parameters on laser cutting of titanium alloy have been investigated. The characters of cut plane and heat affected zone of laser cutting have been analyzed. The experimental results show that the best cutting quality can be obtained when argon is used as an aid-gas. The laser power and cutting speed have of feets on the cutting width and heat affected zone. The cut plane can be divided into two zones which have different appearance. There is a distinguishing boundary between the two zones. The width of heat affected zone on upper surface is narrower than that on lower surface.