[Objective] The spatio-temporal evolution characteristics of the ecological environment in Chengbi River basin from 1988 to 2019, and the causes of its change were studied, in order to provide scientific basis for the protection, management and development planning of the ecological environment in karst area, and scientifically evaluate the change of ecological environment quality in karst area.[Methods] Based on Landsat images, the normalized difference mountain vegetation index (NDMVI) was introduced, and the comprehensive ecological evaluation index (CEEI) model was improved. The ecological environment quality of a typical karst basin in Southwest China, the Chengbi River basin was dynamically monitored from 1988 to 2019. The spatial distribution characteristics of the ecological environment quality in the basin were quantitatively analyzed using spatial autocorrelation methods, and the causes of ecological environment quality changes in the study area were analyzed.[Results] ① CEEI could scientifically reflect the ecological environment quality of the study area. ② The quality of the ecological environment in the research area from 1988 to 2019 was at the middle and upper middle level, and the overall trend was increasing. The low value areas were mainly distributed in the karst peak forest area and surrounding the reservoir area in the northern part of the basin. ③ The ecological environment quality of the study area had a certain spatial positive correlation, but the aggregation gradually weakened. ④ Vigorously carrying out the construction of ecological civilization and the management of stone desertification had greatly promoted the improvement of ecological environment quality in karst areas.[Conclusion] The improved CEEI model can better reflect the ecological environment quality of Chengbi River basin, the average CEEI of Chengbi River basin is on the rise, and the ecological environment quality has been improved.