A good layout of the service facilities in a station can reduce the total walking distance of passengers to and from various facilities. It improves the overall service efficiency and quality of the station. Over time the original layout of a station may become unsuitable. This is often due to the changes in the number of passengers, the types of passengers, and the surrounding environment. In such cases, a comprehensive review of the layout should be conducted. However, the layouts possible are numerous and should be investigated using quantitative evaluation. This paper proposes an integrated model that estimates the total walking time of a passenger by simulation and searches for a near-optimal layout by ant colony optimization. A high-speed railway station is employed as a case study to evaluate the feasibility of the proposed model. The results indicate that the proposed model can effectively save passengers time and improve the service efficiency of the station.