Abstract: In reinforced concrete structure,the reinforcement corrodes and the volume of these corroded products expand to create pressure to the surround concrete of reinforcement.To the assessment of the corroded concrete structure,the most obvious and direct assessment methods are the crack form and crack width.In the lab,concrete cracking process, caused by the rebars corrosion,is simulated by enlarging the pre-located hole on the test pieces.Bulging bolt and water press are used to simulate the stress distribution and crack forms on the memberssurface.Cracking trend of cover concrete,crack developing and crack forms are analyzed on condition of these factors,such as concrete strength,reinforcement diameter,cover depth,reinforcement position,and casting mode.In the end,the finite element method is used to simulate the stress field of a typical test piece.