<p>To explore the unclear processing mechanism and realize parameters optimization of Invar 36 alloy multi-pulse femtosecond laser processing, this paper establishes a two-temperature model for Invar 36 alloy multi-pulse femtosecond laser processing and determine the parameters of the model firstly. Then, a simulation model of Invar 36 alloy multi-pulse femtosecond laser processing is established based on COMSOL software and the effectiveness of the simulation model is verified by experiments. Temperature distribution and multi-pulse ablation mechanism based on process simulation are investigated, with pulse repetition rate <i>f</i>, pulse energy density<i> F</i>, pulse number <i>n</i> and pulse width <i>t</i>_<i>p</i> as influencing factors, and ablation rate and melting resolidification zone (MRZ) range as responses. Four factors and five levels center composite design (CCD) experiments are conducted. An ablation rate prediction model and a MRZ range prediction model of Invar 36 alloy multi-pulse femtosecond laser processing are built. The Pareto optimal solution set for Invar 36 alloy multi-pulse femtosecond laser processing is obtained with the minimum MRZ range and the maximum ablation rate as optimization objectives using genetic algorithm.</p>