Due to chloride ion erosion, freeze-thaw action and other factors, the substructure of underwater bridge is more prone to damage than that of land bridge. However, the current technical condition evaluation code of Bridges in China does not distinguish the weight of each component and structure of underwater Bridges and land Bridges, which leads to the high score of underwater Bridges in the process of technical condition evaluation. This paper uses the Analytic Hierarchy Process (AHP) to re-determine the weights of various components and structures, and employs the entropy weight method to make adjustments. The weights of the substructure components and structure layers of bridges in underwater environments are re-established to facilitate a more accurate evaluation and analysis of bridge conditions. This approach ensures that the evaluation results for underwater bridges better reflect the actual situation.