We obtain varying degrees of corroded reinforcement specimens from prototype and accelerated corrosion members.Using 3D laser scanning,we caculate and statistically analyze the residual cross-sectional areas of each corroded reinforcement specimen.We study the relationship among the comprehensive corrosion rate at the cross-section of corroded reinforced concrete and the overall corrosion rate of corroded reinforced concrete,as well as the number of reinforcements using Monte-Carlo sampling algorithm,and carry out a comparative analysis of the performance characteristics of these two corrosion rate indicators in the assessment of the bearing capacity of corroded reinforced concrete beams.The results show that the generalized extreme value distribution model provide the best fit for the probability distribution of residual cross-sectional areas of corroded reinforcement.The ratio α of the comprehensive corrosion rate at the cross-section and the overall corrosion rate of corroded reinforced concrete decreases as the overall corrosion rate of corroded reinforced concrete and the number of reinforcements increase.On the basis of the comprehensive corrosion rate at the cross-section,the residual bearing capacity of corroded reinforced concrete beam can be predicted more accurately.