Its electric conductivity change markly when TiO 2 ceramic is irradiated with 308nm excimer laser if its fluence is over the threshold,it is transfromed from insulator to semiconductor in room temperature.Analysising and comparing the samples before and after acted by laser with XRD,XPS,microscope methods et al.It can be determined that the procedure takes place because higher fluence excimer laser irradiates on the surface of titania,the temperature on surface rises quickly,a thin layer of the irradited area is molten and then resolidifies quickly,which leads to oxygen deficient so stoichiometric deviates.