Ecopath with Ecosim(EwE)is the core tool of simulating aquatic ecosystem and originated from Ecopath model. The paper reviewed the principle of EwE and its application in the structure and trophodynamics characters of marine ecosystem, fishery management, marine pollution and set of marine protected areas as well as the progress and perspectives in China. The Ewe has powerful simulation and analysis function and the data for EwE modelling are relatively simple; therefore, it has large potentials for application and development in China.