Abstract: In order to study the mechanical properties of carbon fiber reinforced polymer composite (CFRP) confined concrete columns deteriorated in sulfate environment and establish corresponding mechanical models, two types of testing conditions were considered, i.e., deterioration after confinement and confinement after deterioration. Based on the testing results, two quantitative indicators, damage ratio and residual strength ratio were introduced to represent the degree of concrete damage, and a relationship between the damage ratio and the residual strength ratio was setup. Through a regression analysis of the strength and the strain, the models for ultimate strength, ultimate strain and stress-stain relationship were given for these columns, respectively. The results show that with the corrosion time growing, the ultimate strength, ultimate strain and corrosion rate of the CFRP confined concrete are different for the both testing conditions, respectively. Before the pre-deteriorated concrete column is confined subsequently, internal damaged has occurred and will have an effect on its performance. Hence, the effect of initial damage should be considered when CFRP confined concrete columns are adopted in a corrosive environment.