In order to reduce the force of a gun during firing,according to the relevant requirements of the gun,a groove type retreat machine and its main structure size and discharge hole area calculation method were designed.On the premise of meeting the use requirement,in order to make the artillery general layout more compacted,with the optimization goal of reducing the radial size of retreat machine,and the reliability of fluid temperature rise and the sealing device,based on ISIGHT platform,combined with the intelligent optimization algorithm,the optimization calculation was carried out.The results show that the radial dimensions of each component of the optimized retreat machine are reduced,and the weight of the gun is reduced while reducing the recoil force.