Abstract: A front fragile cover is one of the key components of the missile storage and launch box. Its bearing capacity under external pressure was insufficient, which made the safety of adjacent missiles could not be guaranteed. Under the condition that the internal pressure failure strength was basically unchanged, a limiting support mechanism was installed in the front fragile cover. The bearing capacity under external pressure of the front fragile cover before and after the improved design was compared and analyzed by finite element software, and the ground performance test and working test of the front fragile cover were carried out. The results show that the bearing capacity under external pressure of the front fragile cover was greatly improved after the improved design, and the finite element simulation analysis method can be used to guide the performance improvement design of other fragile covers.