The delamination characteristic of optical thin films induced by laser pulse at 1064 nm and its restraining method were studied. The process of delamination was analyzed and the relationship between the area of delamination and the energy of irradiating pulse was deduced theoretically and proved experimentally. Some theories probes to control delamination were done and it was found that irradiation with low energy density pulse could enhance the delaminating threshold and reduce the area of delamination. The effect was found more evident with higher pulse energy density in some range and the mechanism was presented.