Aiming at the problem of uneven coating thickness in the acceleration and deceleration section of Z-shaped spray trajectory on large plane of ship sections,a method was proposed to dynamically optimize spray gun flow in the acceleration and deceleration section of Z-shaped spray trajectory,so as to improve the problem of uneven coating thickness on the whole super-large plane.The reasons for the obvious thickening of the coating thickness at both ends of the super-large plane of ship sections were analyzed.The coating thickness distribution model of spray gun was established without considering the acceleration and deceleration interval,and the spraying speed and spraying spacing were optimized so that the coating thickness of uniform velocity section could met the requirements with considering the acceleration and deceleration interval.Finally,the coating thickness distribution model with dynamic variable flow rate was established to optimize the coating thickness uniformity of the whole super-large plane.Taking the super-large plane of a ship section as an example,the acceleration and deceleration types of acceleration and deceleration interval were equal acceleration and equal deceleration.The effectiveness and feasibility of this method are verified by numerical simulation and experiment.