The data are the railway density of countries along the "the Belt and Road" in 2010. It is the total length of actual railway operation divided by national area in each country in that year, and it is also an important index to measure a country's transportation capacity. The data come from the world bank and their length unit is kilometers per million square kilometers. These data can directly reflect the transportation capacity of countries along the "the Belt and Road" route, and can also reflect the economic development status and development demand of each country from the side. These data set play an important reference role in the common development of China and countries along the "the Belt and Road". Driven by the railway economy, China is closely linked with other countries today and we can do nothing without railway transport, so the railway data are crucial.