An on-line monitoring system of seawater quality based on wireless sensor networks（ WSNs） technology and computer technology is proposed

aiming at alleviating the difficulty of on-site monitoring. The scheme covers sensing layer

network layer and application layer. By attaching the seawater quality sensor to micro-controller and making use of wireless transmission module to realize data collecting of point region

the collected datas are access to the Internet through GPRS module. Upper PC server recieves and processes datas and store result to database.The scheme introduces the layout of WSNs and data transmission and storage process of monitoring network and are described in detail. Upper PC server program and construction of seawater quality database. Feasibility of the scheme is verified by physical set up and experimental verification.