Abstract: Monitoring and evaluation of ecological environmental quality (EEQ) is the basic content of ecological resource management and protection, and a key to promoting regional ecological sustainable development. To systema-tically evaluate the ecological and environmental quality of northern Guangdong, Heyuan City is taken as the study area to assess the spatiotemporal characteristics of EEQ and its driving factors from 2013 to 2021 using multi-source data. Based on the Google Earth Engine (GEE) platform, three periods of Landsat 8 OLI imagery in 2013, 2017 and 2021 were selected, along with MODIS data, meteorological data and land-use data. The spatio-temporal characteristics and trends of EEQ in Heyuan City were analyzed by using Remote Sensing Ecological Index (RSEI) and Moran's Index(Moran's I), and the driving factors of EEQ in Heyuan City were further explored by using geo-detectors. Results indicated that: (1) the mean RSEI of the study area stays around 0.7 in 2013, 2017 and 2021, and the EEQ is generally better; the areas with the RSEI in good and excellent are higher than 70%; the areas with the RSEI grade in improvement are higher than 20%; (2) there is significant spatial autocorrelation of EEQ in Heyuan City, the high-high clusters are mainly distributed in Lianping County, Dongyuan County and Zijin County, while the low-low clusters are mainly concentrated in the Yuancheng District, the junction of Lianping County and Dongyuan County, and the southern part of Longchuan County; (3) the analysis of driving factors of EEQ based on geo-detectors showed that the dryness, greenness, and humidity are the key factors influencing the change of EEQ in Heyuan City, and there exists a dual-factor enhancement relationship among various factors. These findings provide a scientific basis for the utilization and protection of regional ecological resources, and facilitate the high-quality development of the inland cities in the northern part of Guangdong Province.