Aluminum alloy A6061, which is highly resistant to hydrogen entry, was prepared on a carbide steel cylindrical pipe using a magnetron sputtering deposition method. In this method, plasma was generated between the cylindrical pipe substrate and the cylindrical rod targets, and it moved toward the axial direction with the generation of a modulated magnetic field by a low-frequency alternating coil current. Uniform A6061 thin films were deposited inside the cylindrical pipe using the magnetron sputtering deposition method. The surface morphologies of the films were smooth, and the uniformity of the films was increased by the modulated magnetic field. Moreover, hydrogen content measurements revealed that the A6061 plasma coating is highly resistant to hydrogen entry in corrosive environments, suggesting that the coating was applicable to the elastic deformation region of the base material.