Abstract: This paper applies the SOFM (self organized feature map of neural network) classification software, and choose the Landsat temporal TM images in Mays or Junes of 1988, 1994, 2001 and 2003 and applies the five forms of urban expansion identification model considering the ring roads. The results shows that infillment and expansion are the main forms in the three periods of urban growth process from 1988 to 2001, from 1994 to 2001 and from 2001 to 2003, while the linear branch and clustered branch are the main forms in the urban growth from 1994 to 2001 between the fifth and sixth ring roads.