Abstract: The geometric parameter optimization method of flexible skin composed of negative Poisson's ratio honeycomb core and elastic skin was proposed. Firstly, a parameterized modeling method for the flexible skin structure was designed, with geometric parameters such as cell wall length, cell wall Angle, honeycomb height, cell wall thickness and skin thickness. Secondly, the sample points were obtained by uniform experimental design method, the finite element models of flexible skin structure were constructed using the parameterized method, and the structural performance corresponding to various combinations of geometric parameters was obtained through simulation. Then, an approximate model for the relationship between the geometric parameters of the flexible skin and the structural performance was constructed using the response surface method, and the accuracy of the approximate model was quantitatively evaluated. Finally, based on the approximate model, taking the geometric parameters of the flexible skin as optimization variables, and considering the factors such as internal strain, Poisson's ratio, out-of-plane deflection, and mass, a comprehensive optimization objective function was constructed using the weighted coefficient method, and the optimal configuration of the flexible skin structure was obtained by genetic algorithm. A finite element model of the composite flexible skin was constructed to validate the optimization. The results show that compared with the initial configuration, the in-plane deformation capacity is increased by 30.73%, the out-of-plane load capacity is increased by 30%, the structural mass is reduced by 22.77%, and the Poisson’s ratio is reduced by 20.73%.