Abstract: In order to further improve the maintenance quality of railway freight cars, reduce the maintenance cost, and effectively monitor the transport safety of freight cars, it is necessary to accurately grasp the running mileage of freight cars. In view of the existing problems in the calculation of freight cars running mileage, this paper proposed a calculation method of railway freight car running mileage based on the train operation line. The paper integrated the freight car transportation data collected by the railway transportation information integration platform, bound the train operation line to the train formation, generated the freight car operation track, built the mileage calculation model based on the station position relationship in the train operation line network, and implemented the calculation of freight car running mileage. This method makes full use of the existing data resources of the railway transportation information integration platform, implements the tracking of the freight car operation position through the train operation line, increases the density of tracking nodes, and improves the mileage calculation accuracy and intelligence.