The charge passed through concrete is a key parameter for durability analysis of concrete under chloride environment. In this paper, the effect of the water/binder ratio, the replacements of fly ash, slag and silica fume on the charge passed is investigated by analyzing the experiment data and those collected from literatures, so that a multi-factor model is developed. The statistical analysis of data from literature and experiment demonstrates the satisfying accuracy and applicability of the model. The service life of reinforced concrete is studied based on Fick's second law and the multi-factors model, the results show that the reduction of water/binder ratio, or adding the content of blending admixtures can effectively improve the concrete service life. The concrete structures adding slag result in better durability than fly ash. The durability of high performance concrete (HPC) with both of fly ash and slag is better than those with fly ash or slag only.