A fusion method based on improved analytic hierarchy processmultiplication scale method and Shannon entropy is established which includes advantages and characteristics of analytic hierarchy processmultiplication scale method and Shannon entropy. The weight of operation health diagnosing of Honggu Tunnel is studied based on monitoring data by using hierarchical structure of operation health diagnosing model and by considering environment and stress, deformation, crack and water seepage of structure. The study results show that the good effect has been achieved. The results can provide reference for weight determination of operation health diagnosing of immersed tunnels in the future.