Arc-shaped flanged beam structural parts are formed by the laser cladding technology with an inside-laser powder feeding head. The collapse of ends in thin-wall structural parts is avoided with the method of laser energy loading. Due to the feature that tracks with different layer heights can be cladded by using laser beams at different defocus positions, the unequal-height fan-shaped parts can be formed with the variable-attitude radial-scanning method and the curved arc-shaped parts can be formed with the variable-attitude circular-scanning method. The maximum relative dimensional error of the formed parts is -5.9%, the hardness is stable at about 690 HV, and the microstructure is dense and uniform without holes and cracks.