Abstract: In order to investigate and monitor spartina alterniflora resources in the Luoyuan Bay, this paper illustrates the image process and interpretation based on the Landsat TM/ETM+ remote-sensing data of 2000 and 2006. On the base of the spectral analysis of different ground objects, NDVI and tasseled cap transform adopted on multi-spectral images, the algorithms for extracting and rectifying the spartina alterniflora from other landscape types were determined by decision tress classify in combination with visual interpretation. The results showed clearly and truly that the distribution and expansion trend of spartina alterniflora and prove that the remote sensing approach was useful for monitoring smooth cordgrass invasion in Luoyuan Bay. The spartina alterniflora was distributed in coastal wetland around the Luoyuan Bay. The areas of spartina alterniflora were increased 17.657 km2 from 2000 to 2006, and the yearly increasing rate was 10.74%. Meanwhile, the spartina alterniflora was experiencing a quickly expand period and was required to treat with by local government.