This study focuses on the timetable optimization problem in transitional time period. A mixed integer nonlinear programming model is proposed to generate optimal timetable and at the same time maximize the transfer synchronizations. A hybrid optimization algorithm based on the Particle Swarm Optimization and Simulated Annealing is designed to obtain near-optimal solutions. A real-world case study based on the Beijing metro network and travel demand is conducted to demonstrate the effectiveness of the model.