In order to research the relationship between the life of hull with different structure and the reliability while using, a life estimation method for hull based on test was proposed. By assuming that the hull life span satisfied the Weibull distribution, with zero-failure data, confidence limit γ and reliability R, the confidence lower limit of reliable life were given according to test data of the hull life span. If the lower limit of the shape parameters of the Weibull distribution were known, this method can accumulate all of zero-failure data to increase the analysis presion of reliability greatly. At last, using this method, under the hull reliability R and the confidence γ, the confidence lower limit of reliable life with the hull structures as steel, titanium alloy and aluminum alloy were computed. The results indicate that the method is easy to compute and very convenient for engineering application.