Micromachining of crystal materials is a vital technology for fabricating microelectronic device and microelectromechanical system. The technology combined femtosecond laser irradiation and wet etching exhibits advantages in removing femtosecond laser-induced defects and smoothing microstructure surfaces. It also exhibits unique perks in preparing high aspect ratio structures and burying microchannels in materials, thereby facilitating a new approach for micromachining of crystal materials. This study summarizes the technical features, principles, and advantages of femtosecond laser irradiation and wet etching micro-nano processing technique and demonstrates the research progress in fabricating microstructures in crystal materials such as silicon, silicon carbide, and sapphire. The limitations and future advancements of this technology are also discussed.