General marine environmental early warning data have not formed a unified standard, due to the different angles and dimensions in expression of marine environment. General formats of these data are text type, binary type, and mixed type. These data types cannot be read and processed by the GIS platform, so it is necessary to normalize these data to standard format supported by GIS platform. This paper studied the visualization system for marine early warning products which based on MFC framework and Arc Engine development kit and used GDAL and NetCDF function libraries, solved the problem of heterogeneous data sources and realized data production, results presentations, automatic drawing, 3D profile analysis and other functions. It will provide convenience for the comprehensive operation of different types data and improve the visual expression effect for marine early warning products and marine management at the same time. Introduction General marine environmental early warning products include the wind field, three-dimensional thermohaline circulation, storm surge, salt water intrusion, sediment and other numerical early warning products. Due to the non-uniform of the product formats and the different calculation modes, the data analysis and process will encounter various difficulties. Both the establishment of unified operational framework and research of a variety of visualization methods are imperative. Rufu Qin [1] proposed solution that building mixed GIS system for the multi-dimension marine geographic data. Xinfang Li [2] constructed the marine environment visual simulation system by using open source OpenSceneGraph and ArcGIS data process tools. Lingda Wu [4] researched parallel visualization of large scale 3D scalar field. Zhe Bi [5] developed a marine GIS system based on ArcObject, and described the use of AO Library. Jie Huang [6] described the method of spatio-temporal model and visualization for marine environment integrated data. Wenwen Jiang [7] described the method of data formats and data process for marine environment. Jun Gao [9] discussed the modeling of visualization for geospatial data and the role of GIS in the visualization. Chao Tu [10] researched 3D visualization for the ocean temperature field. In the above researches, there is no research on the normalization of the marine currents field data and then building the visualization system for marine early warning products based on GIS. The paper studied the visualization system for marine early warning products. This study solved the problem of heterogeneous data sources. It will provide convenience for the comprehensive operation of different kinds of data and improve the visual expression effect of marine early warning data and marine management at the same time. Analysis and process for marine early warning data Marine environment is a complex giant system, which is multi-coupling, multi-factor, and time-varying. Description, expression and reproduction for the marine environment requires a variety of monitoring platforms and a variety of data acquisition and process which means to cooperate with each other. At present, the basic marine information provided by China includes the 5th International Conference on Computer Sciences and Automation Engineering (ICCSAE 2015) © 2016. The authors Published by Atlantis Press 461 following types: hydrological data, marine biological data, meteorological data, marine stations data, marine chemical data, geophysical data, ARGO data, Modis and other satellites data. Marine environmental early warning data is particularly important in a great deal of marine data due to its dynamic and predictive characteristics. General marine environmental early warning data include wind field, three-dimensional thermohaline circulation, storm surge, salt water intrusion and sediment data. These data have not formed a unified standard, due to its different angles and dimensions in expression of marine environment. General formats of these data are text type, binary type, and mixed type. These data types cannot be read and processed by the GIS platform, so it is necessary to normalize these data to standard format supported by GIS platform. This study selects the ESRI shapefile format as the standard format. The conversion of NetCDF storage format of three-dimensional thermohaline circulation vector data will be described to illustrate the process of data normalization. Data format analysis of NetCDF The full name of NetCDF is Network Common Data Form. NetCDF is a kind of self-explanatory, cross platform data storage and exchange format, which is suitable for scientific data sharing. The data of three-dimensional thermohaline circulation is usually three dimensional data with early warning cycle for one day, which contains three kinds of factors: temperature, salinity and marine current. General data storage format of three-dimensional thermohaline circulation is NetCDF format, opening the NetCDF data through the MeteoInfo software to read the metadata information. The main metadata types include nele node number, node node number, data layers, dimension, time, data length, etc. Process of normalizing data formats It is difficult to use hierarchical color to render vector field directly. The wind field and the wave field are the general vector fields of marine, which are usually stored in NetCDF format that need to be processed and normalized. Data normalization process is as follows