The Tibetan Plateau, characterized by complicated geological structures, is sensitive to climate change and human activities. The vulnerable environmental balance of the Tibetan Plateau has witnessed substantial alterations, emphasizing the urgency to comprehend and protect its ecosystem quality. In this study, we aim to quantify the ecosystem quality of the Tibetan Plateau, portray its spatiotemporal dynamics, and analyze the spatial heterogeneity of climatic and anthropogenic influences. We employed the entropy weight method (EWM) to construct a comprehensive index, termed the Ecosystem Quality Comprehensive Assessment Index (EQCAI). The historical spatiotemporal patterns and trends of EQCAI were subsequently identified. Our results revealed a gradient of decreasing ecosystem quality from the southeast to the northwest of the Tibetan Plateau, while the mitigation of ecosystem quality degradation displayed an improving trend from the southwest to the northeast. We further detected the spatial heterogeneity of factors influencing changes in ecosystem quality through the multiscale geographically weighted regression (MGWR) method. Precipitation emerged as the primary positive factor, exerting a profound influence on the ecosystem quality of the southeastern Tibetan Plateau. Conversely, evapotranspiration, elevation, and human activities negatively affected the western Tibetan Plateau. This study proposes targeted conservation efforts for forestry regions with high ecosystem quality in the southeastern Tibetan Plateau. Additionally, we suggest that the positive impact of human activities on the ecosystem quality of the Tibetan Plateau should be further strengthened. Our findings contribute valuable insights for informed decision-making in the sustainable management and preservation of the Tibetan Plateau's fragile ecosystem.