Abstract: The information of inshore Spartina alterniflora was extracted by using the Landsat images of 1999/2000 and 2006/2007 in Fujian, and the dynamical change of  Spartina alterniflora was analyzed by combination with the GIS data and statistics during the past seven years. The results showed that the decision tree classifier was well applied to extract the information of Spartina alterniflora from the remote sensing images and acquire higher classification precision. In addition, the dynamic monitoring results revealed that the Spartina alterniflora had expanded rapidly and replaced many breed water areas and beaches in seven years from 1999 to 2006 which should be paid attention to, and essential actions should be taken to protect the water bodies and beaches.

Key words: Spartina alterniflora, Decision tree classifier, Expansion, Remote sensing, Fujian province