To determine the index weights of the condition assessment model for suspension bridges, group Analytic Hierarchy Process (AHP) approach was explored to determine the corresponding index weights. Firstly, the 10〖SX(〗0〖〗8.384〖SX)〗～10〖SX(〗8〖〗8.384〖SX)〗 scale method was adopted based on the Weber-Fechner law. Then, the genetic algorithm was used to optimize the consensus of judgment matrixes. The consensus of judgment matrixes was significantly improved after optimization. Moreover, the PSO-K-MEANS clustering algorithm was used to classify the experts' opinions, and the expert weights were calculated by the peer-to-peer consensus reaching model. In the end, the presented group-AHP method was applied to a suspension bridge assessment model to verify its feasibility and practicability. Compared with the index weights of the code, it was found that the index weights calculated in this paper were more reasonable than those of the code. The presented index weights of suspension bridges are the effective supplement to the current standard, which can provide reference to revise the current standard.