Abstract: This study evaluated the evolution of water-land transport efficiency in the Yangtze River Economic Belt (YREB) over 8 years covering the period before and after the implementation of the strategic plan in 2014. Conventional Data Envelopment Analysis (DEA) and three-stage DEA methodologies were employed. Building upon a separate assessment of water and land transport efficiency, a coupling coordination model was applied to analyze their synergistic evolutionary processes. The principal findings were as follows: 1) The overall efficiency of water and land transport remained relatively low, which exhibited a stepwise decline from east to west, with a noticeable improvement in efficiency levels following the implementation of the YREB strategy. 2) External environmental factors had a profound impact on transport efficiency, which was evidenced as a significant contribution to the lower efficiency levels in western provinces and cities. 3) The efficiency of water transport was lower than that of land transport for a certain time. Although there existed a possibility for the coupling of the land and water transport efficiency, the current coordination level was insufficient. The western provinces and cities were found to be the weakest part in the coordination of water and land transport. 4) Scale expansion was a key factor that drove efficiency improvements and regional coordination, though the influence had been gradually diminished. Technological spillover had become a critical factor in promoting the regional coordination of transport efficiency.