本文从土地利用效能和公平性两方面构建评价指标体系，对上海城市蔓延的程度、类型、时空特征和影响因素进行研究。它采用1 km × 1 km网格为空间评价单元，用投影寻踪分类法提高数值分析精度。研究结论如下：1) 1990~2000年期间，上海城市用地以轻度蔓延为主，中度和轻度蔓延型较少，这三类城市蔓延在区县中空间分布差异明显；2) 2000~2010年期间，上海以轻度型蔓延为主，但中度和重度蔓延型占比显著上升。三类城市蔓延型的分布仍以郊区县为主，但分布明显向外推移；3) 针对10个重度蔓延型镇街的个案研究，把蔓延成因归纳为4类：过程性蔓延、大规模工业区建设、高速路网扩张和公共服务设施配套滞后。
This paper establishes an urban sprawl index based on land use efficiency and justice to evaluate the sprawl degree, types, spatiotemporal characteristics and driving forces or urban sprawl in Shanghai. It adopts a spatial network based on grid 1 km × 1 km, and applies Projection Pursuit method for classification of urban sprawl types. The research results are as follows: 1) From 1990 to 2000, the light sprawl was the major characteristics of Shanghai sprawl, and the medium and high sprawl took a small share. The sprawl shows the spatial heterogeneity within different areas of Shanghai. 2) From 2000 to 2010, the proportion of medium and high sprawl increased dramatically, and the outskirts presented a stronger sprawl trend. 3) The cases of 10 high-sprawling townships have shown that the driving forces of sprawl can be classified into four types: sprawl in process, industrial park dominated sprawl, sprawl due to highway construction, and public facilities lagging behind city growth.