Abstract: In order to quantify the large bridge operational risk under disaster weather ,a risk analysis model is put forward .It can be concluded from sample survey that :(1) disaster weathers include :ice ,fog ,snow ,hail ,rainstorm , and wind ;(2) traffic congestion is considered as the index of risk evaluation ;(3) the influence factors of large bridge op-eration risk include :the type of disaster weathers ,level ,duration ,space continuity ,and holiday ,time period ,rate of ve-hicle models ,etc .Based on that ,Fuzzy Analytic Hierarchy Process (Fuzzy-AHP) is established by survey data .This ap-proach can obtain the consequence and probability of risk under the condition of missing objective data ,and provide the decision support for emergency .Finally ,the model validity is tested by the operation situations of Su-Tong Changjiang Highway Bridge .