By the large scale finite element software DIANA, the whole splitting process of concrete protective cover layer due to reinforcement corrosion was analyzed in detail. The simulation analysis shows that the whole cracking process can be divided into four steps, that is, internal cracking, crack growth, external cracking, and penetration cracking. At a certain level of the volumetric expansion ratio of corroded products, the internal cracks initiation at internal side of the concrete protective layer around the steel bar is mainly related to the tensile strength of concrete, and other factors have little effect on it. External cracking as well as penetration cracking are related to the ratio of protective layer thickness to bar diameter. The larger the ratio is, the more difficultly the crack propagation occurs. It is effective to improve the tensile strength of concrete by delaying crack initiation and propagation; under the same conditions, the critical corrosion ratio of reinforcing bar at cracking in non uniform corrosion is lower than that in uniform corrosion; the spalling patterns of concrete protective layer are mainly determined by the ratio of rebar clear spacing to the protective layer thickness(L/C), when the L/C ratio is large enough (larger than 3), only the corner area spalls partly. Otherwise, the whole protective layer will spall.