The utility model discloses a three degree of freedom platform trucks, including the second rail, the walking has second track flatcar on the second rail, the both ends of second track flatcar are equipped with vertical the 2nd hydraulic cylinder who arranges respectively, two one the 2nd wheeled base is installed to the 2nd hydraulic cylinder's flexible end, but a rotation ground roller shaft isinstalled respectively through roller support in the 2nd wheeled base's top surface both ends, a second gyro wheel is installed respectively at the both ends of roller shaft. Be applicable to the maintenance of GIS equipment.