In this paper, an optimum design model for minimizing the life-cycle cost (LCC) of high speed rail road steel bridges is proposed. The point is that it takes into account service life process as a whole, and thus the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs, expected strength failure costs and expected serviceability failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. By processing the optimum LCC design the effective and rational basis is proposed for calculating the total LCC and the sensitivity analysis of LCC is performed. Based on a numerical example, it may be positively stated that the optimum LCC design of high speed rail road steel bridges proposed in this study provides a lot more rational and economical design, and thus the proposed approach will expedite the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.