The invention discloses an adjustable rust-removing and painting device for building steel pipes, which comprises a bottom plate, a support frame is connected to the upper left side of the bottom plate, a feeding box is connected to the left end of the support frame, and a fixing frame is connected to the upper and lower ends of the inside of the feeding box to fix There is a feed roller in the middle of the frame, a fixed cylinder is connected to the right end of the support frame, a rotating screw is installed inside the fixed cylinder, a rotating gear is connected to the outer middle of the rotating screw, a driving gear is meshed at the lower end of the rotating gear, and a driving shaft is connected to the middle of the left end of the driving gear , the left end of the drive shaft is connected to the drive motor, the middle part of the rotating screw is connected to the slider, the outer side of the slider is evenly connected to the guide block, the outer side of the guide block is connected to the installation groove, the middle part of the installation groove is connected to the connecting rod, the right end of the connecting rod is connected to the tie rod, and the middle part of the tie rod A grinding wheel frame is connected, a grinding wheel is connected to the middle part of the grinding wheel frame, and a paint spraying box is connected to the upper right side of the bottom plate. The invention satisfies the needs of derusting steel pipes with different diameters, and at the same time realizes automatic painting of the derusted steel pipes.