科学提取城市建成区信息并探究其扩张的时空特征，对于城市规划和建设有重要的参考意义。在优化局地最佳阈值法的基础上，采用1990年、2000年、2010年、2020年4期PANNDA夜间灯光数据和Landsat系列数据定量提取了白洋淀流域城市建成区信息，其后运用城市扩张指数和景观指数分析了白洋淀流域30年间城市建成区扩张的时空特征。结果表明：运用优化后的局地最佳阈值法成功提取了流域内城市各期建成区的数据，经验证该方法较优化前具有更优的适用性。研究期间白洋淀流域城市建成区扩张显著，增长率达154.48%；流域内35个城市的建成区呈现出较大的规模异质性。时序特征上，建成区扩张总体呈现加速趋势，流域内各城市的建成区扩张速度差距趋于增大；空间特征上，“正定—涿州”线左侧建成区扩张态势低于右侧区域；以莲池区、竞秀区、高碑店市等为代表的市辖区或县级市扩张态势较强。基于景观指数结果，建成区扩张过程呈现“分散-融合”的空间特征，建成区边界呈现“规整-复杂-规整”的演变特征。

The scientific extraction of urban built-up area information and the exploration of the spatial-temporal characteristics of urban expansion have significant relevance for urban planning and management. The local-optimal thresholding method was refined for the quantitative extraction of urban built-up area information within the Baiyangdian Basin, and the extraction process utilized PANNDA nighttime light data and Landsat series data from four periods: 1990, 2000, 2010, and 2020. Subsequently, an analysis of the spatial-temporal characteristics of urban built-up area expansion in the basin over the past 30 years was conducted using the urban expansion index and landscape index. The results show the optimized local-optimal thresholding method is successfully used to extract the data of the built-up areas in the basin for all phases, and it is confirmed that the method exhibits enhanced applicability compared to its pre-optimization state. The urban built-up area in the Baiyangdian Basin experienced significant expansion throughout the study period, with a growth rate of 154.48%. The sizes of the built-up areas across the 35 cities in the basin exhibited high heterogeneity. Temporally, the expansion of urban built-up areas predominantly exhibited an accelerating trend, with a widening disparity in the pace of expansion among the cities within the basin. Spatially, the built-up area to the left of the Zhengding-Zhuozhou line was less developed than that to the right. Notable expansion trends were observed in municipal districts or county-level cities such as Lianchi District, Jingxiu District, and Gaobeidian City. Based on the results of the landscape index, the expansion of urban built-up areas in Baiyangdian Basin shows the spatial characteristics of "dispersion-fusion" during the study period, and the boundary of built-up areas showed the evolution characteristics of "regular-complex-regular".