Based on Baidu migration data，this paper constructs the relationship matrix of population movement，and fully depicts the spatial agglomeration and diffusion process of inter-provincial circulation of Chinese population in the eastern，central and western regions during the spring festival of 2015．The conclusions are as follows: ( 1) February 13th-17th and February 25th-March 1st are respectively the back-home flow and the postganglionic return flow peak periods; ( 2) The inter-provincial flow is char- acterized by both near field and spatial dependency．Beijing-Tianjin-Hebei，Yangtze River Delta，and Pearl River Delta city group led the high-intensity population flows，and form three fan-shaped radiation areas; ( 3) we identify 94 population inflow cities and 242 outflow cities．The population agglomeration along the coastal areas and the population collapse in middle areas form the double vertical pattern of the floating population in China．