In order to study the safety of processing explosives with femtosecond laser， a calculation model of femtsecond laser sequence machining on explosives was established， which took into account the autothermal reaction of the explosives. The processes of femtosecond laser sequence machining on three different explosives （TNT， TATB and HMX） were calculated. The safety of these processes was analyzed. Results show that the frequencies of the femtosecond laser sequence， the heat release of the autothermal reaction and the thermal diffusion coefficient of explosives will affect processing safety. Among these three explosives， the heat release of the autothermal reaction of HMX is the largest， and its thermal diffusion coefficient is the smallest， so its heat accumulation effect is the most significant. Therefore， HMX is ignited when processing with all the three femtosecond sequences with different frequencies （1×10³ Hz， 1×10⁵ Hz and 2×10⁵ Hz）. On the contrary， the heat accumulation effect of TATB is the weakest， so no ignition occurs when processing with the three femtosecond sequence with different frequencies. The heat accumulation effect of TNT is between those of HMX and TATB， so ignition only occurs when using the femtosecond laser sequence with higher frequencies. In the actual machining process， especially for the explosives with greater heat release of the autothermal reaction and smaller thermal diffusion coefficient， femtosecond laser sequence with low frequency should be selected to ensure safety.