Abstract: Based on remote sensing data and the geographic information system processing software platform, we analyzed the eco-environmental quality of Aba Tibetan and Qiang Autonomous Prefecture in Sichuan Province before and after the 2017 8·8 earthquake. We used the Landsat 8 OLI satellite sensor to obtain remote sensing image data of December 31, 2016 (before the earthquake) and December 18, 2017 (after the earthquake), and extracted the normalized vegetation index, humidity component, surface temperature, and normalized soil index as four indices of green degree, humidity, heat degree and dryness, respectively. We used principal component analysis to obtain the Remote Sensing Ecological Index (RSEI) from these four indices. According to the RSEI, the eco-environmental quality of Jiuzhaigou County was categorized as excellent, good, medium, poor and worse. In 2016, 24.8% of Jiuzhaigou County areas were in an excellent eco-environment level, which fell to 19.84% after the earthquake in 2017. In 2017, area proportions of the eco-environment quality at poor and medium levels showed an upward trend, accounting for 17.99% and 33.93%, respectively. The proportion of the area with excellent eco-environment quality in the buffer zone of 15.5 km from the epicenter of the earthquake decreased most, accounting for 5.01%. In summary, the Jiuzhaigou earthquake in 2017 had significant impacts on the eco-environment quality, particularly in the buffer zone of 15.5 km. The Jiuzhaigou National Nature Reserve was most impacted among the three nature reserves of Jiuzhaigou County. Our results provide scientific basis for ecological monitoring, disaster assessment, and restoration in Jiuzhaigou area.