Currently many studies have been conducted to analyze the impact of urbanization on the change of stream structure. However, most of them have concentrated on some developed areas, but the less developed urban areas have attracted few attentions. Taking Nansi Lake Basin as the investigation area, this study analyzed the change of stream structure during the urbanization process. The change of land surface was firstly extracted by using remote sensing images of 1987, 2000, and 2014. Based on the stream structure data derived from topographic maps in 1980s, 2003 and 2014, this study further analyzed the effect of urbanization on spatiotemporal change of stream structure in 30 years by adopting indicators of quantity, structure and connectivity, respectively. The results show that:(1) The construction land increased by 1568.06 km² during the past 30 years. The area of urban construction land has grown significantly since 2000. The percentage of urban population was 32% in 2012. (2) The whole river length, area and river density percentage have decreased by 135.46 km, 2.75 km² and 0.49 km/km², respectively during the study period. In addition, the impact of urbanization on stream structure varied spatially across the study area. The rivers at the low level experienced more significant change, while the water surface rates increase by 59.79% continuously. (3) Although the spatial pattern of stream remained unchanged, the stream structure varied significantly during the study period. The stability value of river network decreased by 4.30%, and the connection rate and the combination degree fell by 21.82% and 21.62%, respectively. Moreover, the urban expansion intensity has strong-positively impacted on the stream. The study helps in better understanding the impact of urbanization on stream structure at different spatial scales and urbanization levels, as well as to provide a valuable support and reference for stream protection.