Abstract: In order to characterize spatial and temporal variation of the eco-environment in quality of the terrestrial ecological red line areas in Wuzhong District, Suzhou City, four indices were chosen, i. e. primary productivity, land surface temperature, land exposure degree and vegetation coverage of the area during the time-frames from July to August in the years of 2000-2015 when the vegetation grew optimally, for the four indices may well reflect eco-environment quality of the area; spatial principal component analysis method was used to build up an eco-environment aggregate index (E_f); co-environmental quality was divided into five grades (Ⅰ-Ⅴ), slope analysis and F significance test of E_f was performed; and slope-directive variances of monthly mean ecological factor (E_f) and ecological factor variation rate (ΔE_f) was explored. Results show that during the period 2000-2015, ΔE_f of the ecological red line areas varied between -0.08 and 0.06, and stayed below zero in about 43% of the areas and beyond zero in about 57%. The eco-environment quality on the whole was on a slowly rising trend, lingering in Grade Ⅱ with E_f being 0.700±0.001. Grading of the red line areas in terms of eco-environment quality shows that 3 in Grade Ⅰ, 7 in Grade Ⅱ, 1 in Grade Ⅳ and 1 in Grade Ⅴ. All the findings in this study may serve as important statistical supports and scientific evidence for protection of the ecological red line areas at Wuzhong District, Suzhou City, and contribute new thoughts and solutions to dynamic monitoring and management assessment of the ecological red line areas.