It has been well acknowledged that Vessel Traffic Services (VTS) has played a growing important role to ensure the safety of navigation in the busy ports and waterways. However, the benefits produced by VTS are usually ignored by the public and private sectors. Besides, the previous evaluations generally exist following problems: (1) It is difficult to collect the data for the parameters in the evaluation models and/or the parameters are designed illogically; (2) Those models did not take the following factors into consideration such as reducing the frequency of coastal vessel patrolling and saving human and material resources; (3) It is difficult to clearly discriminate the benefits derived from VTS and non-VTS. In this paper, a framework is presented to calculate the benefits of VTS in China. Four key indicators (safety, traffic efficiency, environmental protection and reducing supervising cost) and quantitative methods have been introduced into the framework. When calculating the benefits quantitatively, the traffic condition before the construction (expansion) of the VTS has acted as a benchmark. For a case study, the project of the expansion of VTS in Zhoushan Port, East China was evaluated with 10-year data. According to the results, the largest contribution is from the benefit of environmental protection. Via Cost-benefit analysis the benefit cost ratio (B/C) of the VTS is up to 5.248, which shows the benefits produced by VTS are considerable. The research could provide references for VTS benefits evaluation and investment optimizing.