The retrofit priority of existing and retrofitted bridges is examined and compared to determine effectively the seismic retrofit method of bridges. For the retrofit prioritization of bridges a quantitative procedure is proposed firstly based on seismic damage probabilities and total failure cost due to the damage of seismic vulnerable components. Using the proposed procedure, the retrofit priority of four typical girder-type bridges is determined. In addition, the ranking indices of bridges retrofitted by steel jackets and cable restrainers are revaluated for comparing with the results of existing bridges. Application of retrofitting method can considerably decreases damage possibilities of retrofitted components but may increases those of adjacent vulnerable components. Therefore, the seismic retrofitting effects based on the global motions of existing and retrofitted bridges should be examined to determine efficiently the retrofitting method. For evaluating the retrofitting effects the ranking indices obtained from the proposed procedure is found to be utilized effectively.