Abstract: Rapid and accurate assessment of urban ecological quality and its change is of important reference to ecological construction and renovating in high-speed developing urban in central and western regions of China. Taking Jinjiang District in Chengdu City as example and choosing Landsat 5/8 images in 2002, 2009 and 2018, the ecological quality and its change in Jinjiang District from 2002 to 2018 were assessed. The results show that: (1) The values of FVC in 2002, 2009 and 2018 were 0.522, 0.493 and 0.502, respectively. It indicates that FVC of the research area decreased first and then picked up during the period of the 16 years, but the overall trend was in a decreasing state. The values of RSEI in 2002, 2009 and 2018 were 0.526, 0.517 and 0.505, respectively. It indicates that RSEI of the research area decreased in the 16 years. (2) The overall ecological quality in the research area was in ordinary status but continued to decline in 16 years. The decline mainly performed as the decrease of excellent and good quality areas. Ecological quality in the south part of the Jinjiang District, which consisted mainly of built-up areas, decreased dramatically. On the contrary, ecological quality in the north part of the Jinjiang District, which consisted mainly of old quarter, increased in the 16 years. (3) The distribution and variation of FVC was highly consistent with those of RSEI. FVC is the major positive factor for the ecological quality of the research area. With the rapid urban development, the built-up area has become the major negative factor. FVC and RSEI can comprehensively reflect the ecological quality and its change of Jinjiang District.

Key words: Chengdu City, Jinjiang District, fractional vegetation cover, remote sensing based ecological index, ecological quality