Based on the complex network theory, the water system morphological structure characteristics and connectivity in the Baiyangdian Basin were quantified, and the relationship between the water system morphological structure and connectivity was revealed using canonical correlation analysis. The results show that the density of the river network in the Baiyangdian Basin is 0.179 km/km², the river frequency is 0.006 per km², the water system box dimension is 1.129, and the landform development is in the early stage of erosion. The water system ring degree is 0.038, the node connectivity rate is 1.074, and the water system connectivity is 0.360. The overall connectivity is at a medium to low level. In the sub-basins, the Cao River and Pu River basins have good structural connectivity, while the Ping River Basin has the weakest structural connectivity. The importance of river chains varies significantly, with only 5 high and higher importance level river chains, accounting for 19.8% of the total length, concentrated in the main river channels and upstream sections. Low and lower importance level river chains account for 58.6%. The high-value nodes of degree centrality and betweenness centrality are mainly concentrated along the South-to-North Water Diversion Project, while the high-value nodes of closeness centrality are mainly distributed in the entrance area of the Baiyangdian. The water system morphological structure of the basin is mainly driven by the water system box dimension, and the hydrological connectivity index is the key response indicator of water system connectivity. Keywords: water system morphological structure; structural connectivity; functional connectivity; complex network theory; the Baiyangdian Basin 〖FL