Mangrove is a wetland ecosystem with high productivity in tropical and subtropical regions, which is of great significance for maintaining ecological diversity and protecting wetlands. With the rapid development of urbanization and industrialization, human activities such as the use of agricultural fertilizers and pollutant discharge have brought a series of problems. A large number of heavy metal pollutants enter rivers, lakes, seas and soils in different ways, bringing heavy pressure to the restoration of the ecological environment. Leizhou Peninsula Mangrove Nature Reserve, as one of the largest nature reserves in Chinese Mainland, is highly valued. Aiming at the study of heavy metal pollution in Leizhou Peninsula mangrove wetland, this paper proposes a monitoring system for heavy metal pollution in seawater of mangrove wetland. Wireless packet switching technology based on Global System for Mobile Communications (GSM) system, which provides end-to-end and wide area wireless IP connection. The main function modules of the system include: data input, real-time display of monitoring data, data query, data statistics and analysis, decision-making and early warning, early warning information release, etc. Through this technology, real-time monitoring of heavy metal pollution in sea water of mangroves in Leizhou Peninsula can be realized, which can effectively solve the problem of mangrove protection and maintain the ecological environment.