Abstract: Abstract：Introducing spatial interpolation technique and the rank-size rule, this paper discussed the spatial variation patterns and rank-size distribution evolution of cities competitiveness in Urban Agglomeration in the Middle Reaches of the Yangtze River based on the factor analysis method. The results show that : (1) The standard deviation of comprehensive competitiveness of cities in Urban Agglomeration in the Middle Reaches of the Yangtze River assumes to expand, and the relative differences show a trend of wavelike decrease. The spatial patterns present three core-periphery plates structure on the whole and the intra-plate differentiation is obvious, as well as the temporal evolution shows a character of global stability, accompanied with local variation. (2) Each principal factor of comprehensive competitiveness of cities has a dramatic spatial variation. Only city size and economic strength patterns couples well with comprehensive cities competitiveness. The spatial variation patterns of other factors are notably different and affected by urban infrastructure, government, industries, environment, etc. In addition to the track of the first and third principal factor gravity center moving toward geometric center, the rest of factors showing a strong deviation tendency. (3) The size distributions of comprehensive competitiveness of cities in Urban Agglomeration in the Middle Reaches of the Yangtze River and three sub-urban agglomerations generally accord with the rank-size rule, and the evolutions of them are consistent with the spatial variation patterns. The types of size distribution are all rank-size distribution except Wuhan Metropolitan Area, and the fractal features of three sub-urban agglomerations are superior to the whole.