According to the life cycle cost analysis theory, this paper presents a mathematical model of life cycle cost for urban rail transit vehicle. The life cycle phases of urban rail transit vehicle are divided into four stages: procurement, operation, maintenance, recycling and disposal. Then the life cycle costing model is applied to 6A metro train and 8B metro train in order to identify significant cost contributors. Results show that the purchase cost is the highest among all of life cycle cost and the unit vehicle price has a great effect on the total cost. Based on comparison with different train formation plans, it is concluded that the change range of vehicle purchase cost is lower than operating cost and maintenance cost. Thus, when selecting the vehicle type for urban rail transit, all the stage cost should be considered so as to obtain the optimal plan based on the principle of cost minimization.