There are many factors that affect the carbonization life of concrete segments in underwater tunnels，and the prediction methods are not uniform.In this paper，combined with actual engineering，the influencing factors and laws of carbonization of concrete segments in underwater tunnels were analyzed，and three methods for predicting the life of concrete segments were established with the crack limit as the control target.The prediction results of the three methods were compared.The results show that the influence of the temperature and CO2 concentration in the tunnel predicted by the three methods on the life of the tunnel lining structure is basically consistent with the existing experimental rules.The temperature in the tunnel has the greatest influence on the life of the concrete lining，followed by that of CO2 concentration.The three methods obtain non-ideal results in predicting the influence of relative humidity on the life of tunnel lining structure and need to be further improved.The predicted annual average corrosion rate of steel bars after rust expansion of the protective layer is about three times that before rust expansion of the protective layer.Timely detection and repair of cracks can effectively prolong the life of tunnel lining.The prediction result based on XU Shanhua ’s method is the most conservative and slightly smaller than that of the standard method.The predicted value based on YANG Xiaoming ’s method is more than 25% larger than the standard method，and it is recommended based on the actual situation.