The route choice set plays an important role in estimating passenger route choice and consequently calculating passenger flow distribution on an urban rail transit (URT) network. In terms of the problem of the route choice set in the existing assignment model and the cluster characteristics of actual travel times of URT passengers, a URT route choice set validation method based on travel time cluster analysis was proposed. It was developed on the basis of RodriguezLaio cluster algorithm. Taking the Beijing subway network for example, it is found that the proposed method can make rapid identification and rolling validation for abnormal OD on the whole network level, and provide important references for the passenger flow survey of causeanalysis oriented as well as model modification.