The classification accuracy of mangrove is always low due to the similarity of spectra between mangrove and land vegetation,especially water-vegetation mixed pixels.Greenness index and wetness index were extracted based on TM imagery,which can effectively reflect the wetland characteristics of mangrove.The greenness index and wetness index can significantly improve the separability between mangrove and water-vegetation mixed pixels by comparison with NDVI,TM3/TM5,TM5/TM4,which always were employed by other researchers.Knowledge and rules method can significantly increase the classification accuracy of mangrove,compared with conventional classification features and method employed by other researchers.And the Kappa coefficient increased 0.10 while commission error of mangrove class decreased 16.1 percent by using decision tree method.