In this study, the offshore sea area is taken as the research object, and the suitability evaluation set of sea sand mining is established. The analytic hierarchy process (subjective weighting method) and the structural entropy weight method (objective weighting method) are used to calculate the weight of each index in the evaluation set, and the game theory is used to organically combine the two to determine the combined weight of the index. The weighted index layers are superimposed by factors, and the natural breakpoint method is used to divide the suitability of sea sand mining in the study area into five categories: suitable, more suitable, generally suitable, less suitable and unsuitable, and the suitability of sea sand mining in the coastal waters of Guangdong Province is analyzed.