With the increasing shortage of fresh water resources in coastal areas, seawater desalination industry has a broad development prospect. How to select the suitable site of desalination plant has become a hot spot in seawater desalination applications. Taking Hongshiya street as an example, this paper determined the desalination process of the proposed desalination plant by analyzing the characteristics of seawater desalination technology. According to the spatial requirements of the site selection, the candidate plant site was determined by using ArcGIS software, and economic, Marine water quality, social and policy factors ware comprehensively analyzed to select the most suitable site from the candidate plant site. The result shows that this method can intuitively get the suitable plant site of the desalination plant considering various factors, and has certain scientificalness and operability.