Ultrashort laser micromachining for optimization involves a number of parameters, and there are often complex relationships between these parameters, resulting in poor optimization performance of the optimization method. For this reason, a mathematical modeling and optimization analysis method for ultrashort laser micromachining is proposed. First of all, the thermal accumulation effect of ultrashort laser micromachining on the surface is analyzed based on the differential equation of heat conduction, and the mathematical model of ultrashort laser micromachining is constructed according to the analysis results. Then, through the mathematical model, the influence of different polishing parameters on the thermal effect and thermal stress in the processing process is analyzed. Finally, the hierarchical structure is adopted to optimize the distribution uniformity, surface layer depth and hardness of the hardened layer, so as to build the mathematical optimization model of ultrashort laser micromachining and achieve the optimization analysis. The experimental results show that the average machining accuracy is as high as 99%, the lowest roughness is only 5%, and the finish and uniformity are more than 90%, which is of good practicability.