Corrosion of steel bars will lead to cracking of rubberized concrete and reduce the durability of rubberized concrete. The variation of rust expansion reaction caused by corrosion of steel bars can roughly reflect the cracking process of rubberized concrete. Therefore, in this paper, the reaction force of a single steel bar in rubberized concrete caused by uniform corrosion and expansion is studied by mec-numerical simulation. The results show that : (1) With the increase of corrosion degree of reinforcement, the steel rust expansion reaction first increases and then decreases, and the time of the inflection point of rust expansion reaction corresponds to the time of concrete cracking;(2) With the increase of corrosion degree of reinforcement, the mortar in the upper half of the reinforcement is always destroyed first; And the smaller the thickness of concrete protective layer, the easier the rubber aggregate concrete cracking;(3) The thickness of the protective layer remains unchanged, and the larger the diameter of the reinforcement, the easier the rubberized concrete cracks.(4) In the calculation model in this paper, the size relation of the average rust expansion reaction of reinforcement corresponds to the rubber aggregate content of 10%>5%>8%.The research results of this paper have guiding significance for the study of corrosion reaction of rubberized concrete.