This study quantitatively analyzes the coupling and collaborative relationship between digital economy development and ecological environment quality across China's provinces from 2011 to 2021. By employing the coupling coordination degree, decoupling index, and Theil index, the research evaluates the strength and dynamics of this relationship, revealing significant regional disparities and evolving trends. The analysis shows that while the eastern region exhibits a relatively high level of digital economy development with notable internal variation, the central region has shown gradual improvements in coordination. The western region, despite progress, still requires further enhancement. Specifically, provinces like Beijing and Tianjin struggle to balance digital economy growth and ecological sustainability, whereas Jiangsu and Zhejiang have achieved a better synergy. The decoupling index reveals that regions such as Tianjin and Hebei have successfully decoupled economic growth from environmental degradation, while Shanxi and Inner Mongolia exhibit weak negative decoupling, underscoring the need for enhanced environmental protection efforts. Nationally, the coupling coordination degree generally trends upward, though a slight decline in 2021 indicates ongoing challenges in achieving sustainable regional development. Policy recommendations include increasing investment and policy support in the central and western regions, promoting green development, improving ecological environment quality, and fostering interregional cooperation to achieve balanced and sustainable development. This study provides valuable insights for regional policy-making aimed at harmonizing digital economy development with ecological sustainability.