In view of the problem that the main frame of the helicopter fuselage is vulnerable to bullet damage, it is necessary to carry out the research on the bullet penetration damage characteristics of the aluminum alloy main frame structure of the fuselage. To this end, based on the ABAQUS software platform, the revised Johnson-Cook model is used to establish a dynamic model showing the impact of the main frame of a certain helicopter fuselage, and to study the impact of the inclination angle of the bullet and the material of the bullet on the aluminum alloy main body of the helicopter. Damage characteristics of the frame. The results show that the inclination angle of the warhead affects the penetration ability of the bullet, but there is a critical value for this effect. Before reaching the critical value, the penetration ability of the bullet increases with the decrease of the inclination angle. After reaching the critical value, the inclination angle continues to decrease and no longer increases the penetration ability. At the same time, as the inclination angle decreases, the damage area of the main frame first increases and then decreases. The damage area is the largest when the inclination angle is 45°. The bullet material affects the strength and stiffness of the bullet, and affects the penetrating ability and destructive ability of the bullet. The calculation results show that the penetrating ability of the copper bullet is greater than that of the steel bullet, and the destructive ability of the steel bullet is greater than that of the copper bullet.