Based on the DMSP/OLS nighttime light data for the years 1993-2012 and spatial analysis methods including standard deviational ellipse and rank-size distribution, this paper systematically analyzes the spatial structure and spatiotemporal dynamics of the urban system in countries along B & R (The Belt and Road Initiative). We found that nighttime light increased in most countries along B & R. These fast growing countries are undergoing economic reforms and post-war reconstruction, while nighttime light reduction occurs in areas of social and economic unrest. The trend of size distribution of nighttime light in B&R is continuous spatial expansion, and the center of the nighttime light is moving to southeast Asia. The nighttime light distribution in the top 2000 urban places in B&R follows the rank-size distribution, thus urban land distribution is more concentrated than the past. The high rank cities are fairly well developed, but the development of the small cities is lagging behind. The general distribution trend toward, concentration is stronger than decentralization in B&R.