To study the effect of corrosion on the axial compression performance of the upright tube of steel tubular scaffold with couplers, the surface morphology of the inner and outer walls of the steel tubes with different degrees of corrosion was analyzed, and the degradation law of the mechanical properties of the corroded steel was discussed. The calculated formula for the stability of the corroded steel tube was proposed through the results of the axial compression tests. The research results show that pit corrosion develops from independent pits to ulcer-like pit groups with an increase of the quality loss rate. The pit corrosion ratio, the average arithmetic height, and the root mean square height of the outer wall are higher than those of the inner wall. Randomly distributed and different sizes of pits will cause the strength and plastic deformation of the steel to decrease. Compared with the decrease in strength, corrosion has a more severe impact on the plastic deformation ability of steel. The axial compression failure mode of steel tubes with different corrosion degrees is the overall bending instability. As the mass loss rate increases, the ultimate load decreases linearly, and the axial displacement value corresponding to the peak load point gradually decreases.