This paper analyzes panel data from 2003–2012 to identify the factors driving the expansion of construction land in Ningbo city; it uses panel data, regional-level, and year-by-year regression models. The results indicate the following: (1) For each 1% increase in the size of the economy, urban population, and industrial structure adjustment coefficient, the amount of construction land increased by 0.35%, 0.52% and -1%, respectively. (2) The factors driving the expansion of urban construction land differed across regions. In more highly developed areas such as Yuyao, Cixi, Fenghua and the downtown area, population growth was the most obvious driving factor with coefficients of 4.880, 1.383, 3.036 and 0.583, respectively, in those areas. Here, the impact of industrial structure adjustment was lower than that of population growth (with coefficients of 1.235, 0.307, 0.145 and -0.242), while economic development was an increasingly insignificant factor (with coefficients of -0.302, 0.071, 0.037 and 0.297). On the other hand, economic development was the most important factor for the expansion of construction land in relatively less developed areas such as Xiangshan and Ninghai counties with coefficients of 0.413 and 0.195, respectively. Here, population growth (with coefficients of -0.538 and 0.132) and industrial structure adjustment (with coefficients of -0.097 and 0.067) were comparatively weaker driving factors. (3) The results of the year-by-year regression indicate the increased impact of economic development as a driving factor (from -1.531 in 2005 to 1.459 in 2012). The influence of the population growth factor slowly declined (from 1.249 in 2005 to 0.044 in 2012) and from 2009 on was less influential than the economic development factor. The industrial structure coefficient remained negative and its influence diminished from year to year (from -5.312 in 2004 to -0.589 in 2012).