With the rapid development of urban rail transit in China，the operation volume and scale of urban rail transit are growing rapidly，and operating costs are also rising. Now，the ticket revenue of most operating enterprises cannot cover the operating cost and the rapid growth of costs and capital gap has become increasingly prominent，the lean management ofoperating cost is of great practical significance to the sustainable development of the industry. Based on the investigation of the key operating costs of rail transit enterprises，this report analyzes the key cost factors from the three aspects of labor cost，energy consumption cost and maintenance cost. It found that the key cost influencing factors mainly include the number of employees，employee compensation，equipments size and energy consumption price. The change and development trend of operating costs are analyzed and some proposals are put forward，including improving labor efficiency，enhancing the value of human capital，implementing accurate control of energy consumption，improving standardization of cost management and cost lean management.