A new recoil structure was put forward for certain type vehicle-mounted multi-barrel gun. One recoil mechanism is shared by four tubes, a counterweight block is added to increase the mass of gun recoiling part, and then achieve the purpose of gun recoil force reduction. The multi-barrel gun can achieve vehicle. The numerical simulation model was established with Fortran by the analysis of the structure. The results showed that the recoil force of the gun was reduced more than 80% and the recoil length was controlled well because of the structure.