The launching process of 80 mm finite space tube type weapon braking system was calculated and simulated by the finite element method in this paper, and the energy absorbing effects of deformation ring made of 10 steel, 20 steel and 35# steel respectively were compared. The calculation results showed that when the deformation ring adopted 20 steel, the system collision time was the longest, the piston displacement distance was the largest and the ability of absorbing impact energy was the strongest, which made the axial tension of the system the smallest. According to the comprehensive calculation results, 20 steel was selected as the deformation ring material. Finally, the live firing experimental investigation of the deformation ring made of three kinds of materials was carried out, and the experimental results showed that the finite element calculation result was correct and feasible.