This paper discusses the role and the importance of three parameters, that is, the flange height, the flange thickness and the comprehensive value of the flange. Based on the actural wear data of the wheel flange in some urban rail line, the effects of the three parameters on the wear of wheels of a vehicle are analysed. It is shown that this line is a typical tread wear line; the virtual thickening flange is common for the vehicles of the line, the asymmetric wear on the wheel flange can be found in the first and fourth shafts of the trailer car. Finally, some suggestions on how to improve the service life of the line are proposed. For example, the proper adjustment of the wheel-rail hardness ratio, the regular reverse operation, the adjustment of the force distribution for the trailer air braking and moter car electric braking, reducing the proportion of the air braking point velocity and other methods to reduce the wheel wear, improve the safe operation of the urban rail vehicle.