This paper presents the corrosion-induced cracking process of a corroded reinforced concrete beam exposed to a chloride environment for 26 years. The cracking maps of the beam were drawn during different corrosion periods. The first corrosion-induced cracks in the compression zone occurred at about the 5th year and then developed significantly. The corrosion-induced cracks in the tension zone appeared at about the 7th year, followed by the stirrup zones in the transversal sections. At about the 14th year, the width of the cracks in the tension zone exceeded that in the compression zone. The cracks in the tension zone became connected almost throughout the span. The top-bar effect, bleeding and the "top surface ponding effect" led to the appearance of corrosion-induced cracks first in the compression zones, while the corrosion-induced cracks in the tension zone increased more significantly in both length and width as a result of the sustained load.