To evaluate the calcium leaching for the concrete subjected to aggressive water, a two-dimensional calcium leaching model of concrete is established based on the leaching mechanism of concrete under the effects of soft water and nitric acid. The tortuosity and the constrictivity of the concrete are incorporated into the model. The effect of the interface transition zone(ITZ)on the porosity is also considered. The reliability of the model is validated by the comparisons between numerical and experimental results. The theoretical model was solved using COMSOL software and the characteristics of the two-dimensional calcium leaching of concrete was analyzed. It shows that the leaching depths of concrete subjected to soft water and nitric acid are proportional to the square root of time.