At present, the rapid development of micro-machining and finishing technology has put forward higher requirements for miniaturization processing technology: the processing scale needs to be improved to the micron or even nanometer scale, and three-dimensional micro-machining can be achieved inside the material. Femtosecond laser can break through the limit of diffraction limit and machining limit, and is the hot spot of advanced manufacturing technology. In this paper, the development and mechanism of femtosecond laser machining are reviewed, and the mechanism of laser machining is described from the Coulomb explosion model, microexplosion model, color center model and two-photon ionization model. For femtosecond laser ultrafast action process, simulation is the main means to analyze the machining mechanism and study the laser and material action process. The characteristics and application range of the two-temperature model, molecular dynamics model and composite model used in femtosecond laser simulation are analyzed in order to provide a basis for the theoretical research of femtosecond laser machining. Finally, the existing problems of femtosecond laser machining technology are pointed out, and the development of this technology is prospected.