n 1-on-1 case the influence of laser conditioning on the microscopic morphology and structure of HfO_2 optical thin film is studied. The HfO_2 thin films were irradiated with 10%,30%,50% and 70% of the threshold energy in 1-on-l. In order to research the microscopic morphology of HfO_2 optical thin film,the film surface areas of 10 m* 10 m and 3 m* 3 m were tested with atomic force microscope. Comparing laser conditioning with non-laser conditioning, the thin film being irradiated contains less impurities and its cone-shaped structure becomes smooth. The microscopic structure of thin film was tested with X-ray diffraction and X-ray photoelectron spectroscopy. Comparing laser conditioning with non-laser conditioning, the crystalline structure, the chemical bond and the element valence of thin film being irradiated are not changed. The components of thin film were tested with X-ray photoelectron spectroscopy. Comparing laser conditioning with non-laser conditioning,the thin film being irradiated contains less hafnium and more oxides of hafnium. The experimental results show that the laser conditioning plays an important role in polishing and oxidizing HfO_2 thin film.