Urban construction land plays an important role in economic development in China. This study explores the driving forces of urban construction land expansion. Panel data econometric method was used to analyze relevant data of China during the period 1999 to 2008. The results showed that: 1) Urban construction land had been expanded very quickly in East China, Central China, West China and the whole country. The rate of expansion was the highest in East China, and was declining in recent years. But it was relatively slow in Central and West China. 2)Economic development, the increasing urban population and industrial structure adjustment can explain the expansion of the urban construction land of East China, Central China, West China and the whole country very well, those three variables all have positive effects on urban construction land expansion, while the influence strength varies in different regions. 3)Year by year regression results show that: economic development, the increasing urban population and industrial structure adjustment also have positive effects on the urban construction land expansion, which indicates the influence of increasing city's population on urban construction land expansion is stable, while the influence strength of population growth is greater than those of the economic development and industrial structure adjustment, in addition, the effect of the economic development on urban construction land expansion becomes increasingly stronger, while the influence strength of the adjustment of industrial structure on urban construction land expansion becomes increasingly weaker.