Loads has an important influence on chloride ion diffusion in concrete,then we build a mathematic model of the chloride ion diffusion,by means of the chloride ion diffusion in concrete mechanism analysis,considering the temperature,the binding force,time,fly ash content,concrete strength grade and other factors as well.When Crebar/Cext is 0.3,the ordinary concrete′s service life is 11.23 years,but the ser-vices life of different fly ash content concretes were 13.21years,14.77 years,17.56 years,20.02 years,which increase 35%,87%,108%,299%respectively.And fly ash content is linear relationship with growth rate.With the loads,while Crebar/Cext is 0.3,stress-free concrete′s service life is 62.72 years.When the compressive stress ratio is 0.2,0.4,0.8,Service life of reinforced concrete structures were 74.55 years,95.99 years, 35.37 years,increasing 18.86%,53.05%,-43.61% respectively.When the tensile stress ratio is 0.2,0.4,0.8,the service life of reinforced con-cretestructures were43.91 years,31.10 years,21.49 years,reducing 29.99%,50.41%,65.74% respectively.When Crebar/Cext=0.3,C35 and C55 ser-vice life of reinforced concrete structures were 74.55years,114.23years respectively.%由于荷载对氯离子在混凝土中扩散产生重要的影响，通过对氯离子在混凝土中扩散机理的分析，并综合考虑温度、结合力、时间、粉煤灰掺量、混凝土的强度等级等影响因素，建立起了氯离子扩散的数学模型。运用多物理场耦合软件 Comsol Multiphysics 建立数值模型研究表明：当阀值 Crebar/Cext=0.3时，普通混凝土服役年限为11.23年，不同掺量的粉煤灰服役年限分别为13.21、14.77、17.56、20.02年，同比增长了17.63%、31.52%、56.37%、78.27%，增长的比率与粉煤灰的掺量成线性关系；在荷载作用下，当阀值 Crebar/Cext=0.3时，无应力混凝土的年限为62.72年，压应力比为0.2、0.4、0.8时，钢筋混凝土结构的服役年限分别为74.55、95.99，35.37年同比增长了18.86%、53.05%、-43.61%，拉应力比为0.2、0.4、0.8时，钢筋混凝土结构的服役年限分别为43.91、31.10、21.49年同比减小29.99%、50.41%、65.74%；当阀值 Crebar/Cext=0.3时，C35、C55钢筋混凝土结构的服役年限分别为74.55、114.23年。
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