Both aviation and high-speed rail are developing rapidly, which promotes the popularity of intermodal services. However, most cooperation only comes from political support. Operational measures should be taken for further improvement. In such circumstance, a model is proposed in this study to improve the quality of services and strengthen the connectivity between two modes by optimizing the railway timetable. The model is set to maximize the connection numbers of two modes. To take journey is "air-rail" or "rail-air" into consideration, we divide passengers into four groups. The original model is linear and can be calculated by commercial solvers. The models were applied on a case China. The results showed that the model is effective, the connection numbers improved by 40.2%
