The normalized difference water index (NDWI)

normalized difference water index based on blue light (NDWIB) and combined index of NDVI and NIR were applied to water body identification (CIWI)

and the discrimination to farmlands

roadways and settlement places was calculated using HJ1A/1B CCD date of 300 samples from the Hainan Island. The discrimination of CIWI water index model is the highest

with the comprehensive discrimination of 34.61% and it is the optimal model of water recognition in the Hainan Island. The best recognition threshold of CIWI water index model (168.54) was confirmed. It was used to extract water information on 24th of February and 24th of September

2014 efficiently

with the total island water area of 677.41 km

2

and 698.62 km

2

respectively. The total accuracy of water extraction reaches 92.00%. The CIWI water index model has the advantages of large discrimination of land and water and high precision extraction of water area

which can be used to extract water information of Hainan Island. This paper provides reference for optimized allocation and management and dynamic monitoring of flood disaster for water resources in Hainan Island.