A muzzle brake with composite structure is proposed to reduce the mass and resist ablation. The muzzle brake with composite structure is composed of inner structure and outer structure, whose inner structure is made of gun steel and whose outer structure is made of titanium alloy. Based on the transient dynamic load which is calculated from muzzle flow field with muzzle brake, the strength analysis of muzzle brake with composite structure is operated via fluid solid coupling method. The results show that the muzzle brake with composite structure can meet the required strength, and its mass is much smaller than that of muzzle brake which is made of gun steel, it opens a new avenue for the design strategies of high-performance muzzle brake.