Based on river structure data in 1960s, 1980s and 2009, the change characteristics of river structure of urban central area in Hangzhou City of Zhejiang Province nearly 50 years were analyzed with river density, water surface ratio, development coefficient, river network stability, connection rate and practical combination degree from aspects of quantity, structure and connectivity features. Results showed that:(1) The length and area of the whole river network showed a decreasing trend except that in the secondary river in 1960s-1980s had a small increase. River density and water surface ratio showed decreasing trends since 1960s.(2) Compared with 1960s, development coefficient of river network increased in the secondary river and reduced in the tertiary river in 1980s, which decreased in 2009, the river stability also decreased.(3) River connection rate and practical combination degree decreased, which made the river connectivity decrease slightly in 1960s-1980s. While in 2009, the river connection rate and practical combination degree decrease dramatically, the river connectivity also decreased distinctly, which made the flood risk increased simultaneously.