This paper evaluates several key approaches for their impact on the development of insensitive munition (IM) with special emphasis on the fuze. The effect of these approaches on the thermal vulnerability of a fuze is studied and evaluated by finite element analysis. These approaches include changing the proportion of the desensitizing agent, replacing the charge, changing the shell material, and adding the heat insulation coating. Firstly, the cook-off test of a PBXN-5 (plastic-bonded explosive number-5) squib tube is simulated by ABAQUS and compared with the test results to validate the soundness of the proposed method. After this, comprehensive evaluations are conducted on each approach for its influence on the cook-off time. The results suggest that the weighting on the four proposed approach from high to low are insulation design, the insensitive charge, the shell material, and the proportion of the desensitizing agent, respectively.