In order to study the stress distribution of steel bar with corrosion pit after exposure to high temperature， specimens with artificial corrosion pits were prepared， then the high temperature was exposed and tensile tests were conducted to investigate the variability in mechanical properties. The stress distribution near the artificial corrosion pits was simulated by finite element analysis. The results show that for the specimens with single artificial corrosion pit， its stress concentration factor of the specimen with hyperbolic corrosion pit is greater than that with elliptical pit. When the width of the artificial corrosion pit is constant， the stress concentration factor increases with the increase of depth to width ratio. After experiencing 800 ℃， the stress concentration factor is reduced by about 10%. For the specimen with two artificial corrosion pits， the stress concentration factor significantly increases when the angle of corrosion pits is between 30° and 90°.