Aiming at the increasing requirement of the maximum muzzle velocity of an aircraft gun, the arc thickness and propellant quantity were optimized to improve the maximum muzzle velocity. Whale algorithm, which has the advantages of simple operation and strong ability to jump out of local optimum, is selected to optimize the interior ballistic performance by combining the whale algorithm with the interior ballistic mathematical model of the gun. The results show that the optimization effect of this method is good, the maximum muzzle velocity has been effectively improved, and the combination of the whale algorithm and interior ballistics is feasible, which provides a certain reference for the interior ballistic design of other types of guns.