Abstract：By the simulation corrosion test of loaded and unloaded bolts in moist air and Na2SO4 solution，the relation curves of the mechanical performance with the corrosive conditions and the corrosion time are given. The mechanical performance is compared between these two types of bolts. At the same time，the influential trend of the load on the mechanical performance of the corroded bolt is analyzed. The test results show that：(1) after being corroded in the moist air，there is no prominent difference in mechanical performance between loaded bolt and unloaded bolt；but after being corroded in Na2SO4 solution，both the ultimate bearing capacity and the maximal tensility of loaded bolt decrease far more than those of unloaded bolt，and the endurance and service life of loaded bolt will also be shortened much more severely.
