The invention relates to a one-step shaping technology for coating epoxy powder on the inner wall and the outer wall of a steel pipe. The one-step shaping technology for coating the epoxy powder on the inner wall and the outer wall of the steel pipe is characterized in that epoxy powder spraying of the inner wall of the steel pipe and epoxy powder spraying of the outer wall of the steel pipe are carried out simultaneously in one production line; the production line comprises an internal movable epoxy powder spraying trolley, an internal epoxy powder spraying rod, a support rail trolley, a spray nozzle, a spiral conveyer roller path, pipe delivering trolleys, the steel pipe, a medium frequency heating coil and an external epoxy powder spraying chamber; the external epoxy powder spraying chamber is arranged in the middle of the production line, the medium frequency heating coil is arranged on one side of the internal epoxy powder spraying rod nearby the external epoxy powder spraying chamber, and the medium frequency heating coil can be used for finishing heating of the inner wall and the outer wall of the steel pipe at the same time; and the epoxy powder spraying of the inner wall of the steel pipe and the epoxy powder spraying of the outer wall of the steel pipe are finished at the same time in the production line. The one-step shaping technology for coating the epoxy powder on the inner wall and the outer wall of the steel pipe has the advantages that the technological layout is compact, the spraying of the inner wall of the steel pipe and the spraying of the outer wall of the steel pipe can be finished at the same time, the occupied area is small, work efficiency is high, energy is saved, and the one-step shaping technology for coating the epoxy powder on the inner wall and the outer wall of the steel pipe is suitable for anti-corrosion coating treatment on inner walls and outer walls of steel pipes with various diameters.