Exports are a crucial driving force of China’s economic growth; however, researchers have yet to verify whether they can effectively improve the high-quality economic development. Based on interprovincial panel data from 2000 to 2019, in this study, we constructed a high-quality economic development indicator system through the entropy weight method, and we adopted the linear regression model and dynamic panel threshold model to empirically test the export trade effect on the high-quality economic development as well as its mechanism. We also probed the impact of the heterogeneous absorptive capacity on the high-quality economic development. According to our research findings, China’s export trade has substantially promoted the high-quality economic development level by, from the viewpoint of the action path, positively influencing the economic, open, and coordination subsystems. The influence of the export trade on the high-quality economic development has a substantial single-threshold effect on the heterogeneous absorptive capacity; that is, when the threshold variables that represent the regional absorptive capacity (the economic level, R&D intensity, and technological gap) are all higher than the threshold value, the export trade has a substantial positive impact on the high-quality economic development level. The research conclusions of this paper provide new ideas for the development of high-quality economic systems as well as a useful reference for China in its formulation of more targeted foreign trade policies.