The work aims to investigate the influence of surface imperfection on corrosion behavior and mechanism of 13Cr tubing in gas well acidizing process by studying corrosion behavior of super 13Cr tubing samples with smooth surface, nondefective surface and defective surface in gas well acidizing and capacity increasing revamp process. High temperature high pressure simulation experiment was completed to study the corrosion behavior of as-received tubing samples in three conditions gas well acidizing process in live and spent acid. Macro-, micro- and 3D morphology of the samples being corroded in live and spent acid was analyzed with optical microscope, SEM, and 3D confocal microscope. In live acid, corrosion rate of nondefective as-received surface sample was almost equal to that of defective as-received surface sample, but corrosion rate of smooth surface sample was much lower. In spent acid, corrosion rate of the nondefective as-received surface sample was 7.3 times of that of the smooth surface sample, and 2 times of that of the nondefective as-received surface sample. Surface state of super 13Cr tubing has a substantial influence on its average corrosion rate and local corrosion rate in gas well acidizing process, imperfection on internal surface reduces corrosion resistance of 13Cr tubing in both acidizing processes. Moreover, such imperfection has a greater influence on 13Cr tubing corrosion in spent acid than that in live acid.