The invention relates to a vehicle mark spraying device of a railway freight train. The device is composed of a movable train body (1), a movable train body driving motor (2), a sliding rail truss (3), a gas pressurizing cylinder (4), a powder pump (5), an electric spray gun (6), a spray gun sliding assembling bench (7), a spray gun sliding assembling bench driving motor (8), a spraying powder pot (9), a sliding rail (10), a vertically moving cylinder (11), a travelling rail (12) and an electrical and PLC automatic control system (13). The vehicle mark spraying device of the railway freight trains is characterized in that the device controls the electric spray gun (6) to automatically perform train inspection and maintenance mark spraying to the railway freight trains, which are stopped on a fixed inspection and maintenance work position, in different kinds and models through the electrical and PLC automatic control system (13). The vehicle mark spraying device is mainly advantaged in that steel templates for the train inspection and maintenance mark is replaced. The vehicle mark spraying device can be use by single operator so that a labor operation time and a labor cost are reduced. The operator is free from being contact with a to-be-sprayed target during a spraying process in a short distance so that an operation environment is improved. Sprayed characters are order and specified in arrangement and are clear in writing.