<p>Assessing shoreline changes is of great importance for understanding the dynamic interplay between human activities and ecosystems within coastal regions. In this article, we provide an evaluation of the changes in shoreline positions and the transformation of shoreline types along the entire coast of mainland China during various time periods after the Chinese economic reform using Landsat imagery. The results show a shift in the proportion of natural shorelines, changing from being in the majority (82.7%) to becoming the minority (32.4%) between 1980 and 2020. In addition, the accretion of shorelines was the dominant phenomenon. Shoreline changes were primarily driven by economy-oriented human activities and were clearly influenced by the stages and spatial patterns of China’s economic development. In the early stage of the Chinese economic reform, the loss of natural shorelines was primarily driven by the expansion of aquaculture and agricultural land, which required less capital investment. However, over the past couple of decades, a considerable quantity of shorelines has been converted into quays and construction shorelines, as coastal regions had more capital and supportive policies to invest in the construction of quays, infrastructure, and residential buildings. Given the growing population and increasing human activities in the coastal regions, these regions will encounter escalating challenges in the future. This underscores the need for research and implementation of mitigation and adaptation measures. The relationship between human activities and shorelines, as unveiled by this investigation, can provide valuable insights for preserving natural shorelines while fostering development in coastal zones of other nations.</p>