To better understand the agricultural resources and environmental problems of the provinces along The Belt & Road in China, it is critical to investigate their agricultural carbon emission efficiency and evolutionary trends.

Based on the panel data of 18 key provinces and cities between 2006 and 2015, this paper evaluated the agricultural carbon emission efficiency with the data envelopment analysis Malmquist model and further explored their dynamic evolutionary trends.

There were several main findings. First, the efficiency levels of agricultural carbon emissions showed significant regional differentiation among the areas, with that along the 21st-Century Maritime Silk Road being much higher than that along the Silk Road Economic Belt.

Second, technical efficiency was the key factor that restricted the improvement of the comprehensive efficiency of agricultural carbon.

Third, most provinces invested in too many redundant and unreasonably allocated resources, showing a trend of diminishing returns to scale.

Last, According to dynamic evolution analysis, the total productivity still demonstrated a diminishing trend.

This paper provides some suggestions for effectively improve the efficiency of agricultural carbon emissions in China, such as optimise the agricultural industrial structure, increasing the investment of carbon emission reduction technology, and implementing a carbon emission quota clearing system.

This paper contributes to the improvement of the environment in China.