The free-form surface roof structure is widely used in large-span public buildings due to its beautiful shape. Its grid division form is diverse, and the size and shape of the structural grid directly affect its bearing performance. In this paper, the grid optimization research is carried out for the free-form surface single-layer reticulated shell roof, based on the Rhino platform and the grasshopper module for parametric modeling. The karamba plug-in is used for structural analysis, and the roof structure of different grid divisions under various load conditions is analyzed, computing its response and its carrying capacity. Genetic algorithm is used to optimize free-form surface roof structure, with grid density, member bar length and section size as parameters. Comprehensive consideration of structural self-weight and maximum displacement and other design goals are considered. It provides reference for the design of free-form roof structure.