Well-developed and efficient public transport systems are adopted as one of the important public policy in many countries. A comprehensive public transport system can meet the basic transportation needs of the people. However, transfer is unavoidable when public transport is used as the main carrier. The concept of ”Seamless transportation” gradually formed aiming to reducing the “transferring gap” and to improve the service quality of public transport systems. The main contribution of this research is to identify these “transfer gaps” from various aspects and offer a theoretical and easy-to-implement mechanism to evaluate these gaps. An integrated index is also proposed to fusion the gaps found in different aspects. Based on these index values, gaps can be identified easily and effective action plans can be drawn.