In this paper, the fuzzy C-means clustering algorithm( FCM) is applied to the mining of marine environmental monitoring data. The data of the sea area of Laizhou Bay, including pH value, temperature,dissolved oxygen concentration, and so on, are analyzed by data preprocessing algorithm. FCM algorithm is used to cluster the data of different sea areas, so as to obtain the data characteristics of similar sea area. The algorithm is applied to the prediction of seawater pollution,which is used to distin-guish between the polluted and non-polluted seawater samples. The results show that the algorithm is ef-fective and provides a new way for the early warning of sea water pollution.