Abstract: Optical window materials such as diamond, zinc sulfide and silicon carbide possess excellent mechanical and optical properties, which are key materials of infrared imaging guidance systems. Ultra-short pulse, high-instantaneous-power femtosecond laser have become powerful tools for processing optical window materials like diamond, which solves problems such as mechanical damage, cracking, high roughness and residual stress that exist in traditional processing technologies such as mechanical machining, chemical etching and micro-discharge processing. The nonlinear energy absorption, non-equilibrium state energy transfer and the material removal mechanism of femtosecond lasers interacting with wide bandgap optical window materials were first reviewed. The research on femtosecond laser processing of optical window materials such as diamond,zinc sulfide and silicon carbide and their typical applications was analyzed. Finally, the problems still existing in femtosecond laser processing of optical window materials and the corresponding strategies were summarized.