The utility model discloses a closed freight vehicle with a movable top cover, which aims at the problem that the top cover of the existing freight vehicle is inconvenient for disassembly. The freight vehicle with a movable top cover comprises a movable top cover positioned at the top end of a carriage of the freight vehicle, a supporting arm which is connected with the movable top cover and is provided with a rotating shaft of which one end is provided with a chain pulley, a rotating shaft base arranged on the upper end of the carriage, and a hydraulic device which comprises a power source, two single-stage hydraulic cylinders, a connecting rod, a chain and an oil pipe, wherein the chain is engaged with the chain pulley. One end of the chain is connected with the single-stage hydraulic cylinders, and the other end of the chain is respectively connected with both ends of the connecting rod; the power source is connected with the single-stage hydraulic cylinders through the oil pipe. The utility model has the advantages of simple operation, high safety and reliability, simple structure and high durability.