[eng] Mass tourism has emerged in many islands as holiday destinations. It’s a double-edged sword: on the one hand, it brings a lot of economic benefits to these islands; on the other hand, overusing the natural tourism resources makes the environment deteriorated. For developing a sustainable tourism economy, it’s necessary to protect the environment. This paper concludes the negative impacts on islands caused by unscientifically-developing mass tourism. For solving these negative impacts, environmental policies are emphasized. This paper takes Hainan (a Chinese island) as a case and try to provide some useful and practical environmental policies for its environmental protection.