Building harmonious society is one of the most important aims for China nowadays and the problem of severe imbalance
between human and nature must be solved firstly. Geographic information system (GIS) can play an all-important role to
help to this issue. Along with the rapid urbanization, it is very prominent that the agricultural lands converted to building
lands, especially, in some metropolitan areas. This study took Lanzhou metropolitan area in West China as an example.
Firstly, based on interpretation on the TM 2, 3, 4 integrated images 1986 and ETM + 2, 3, 4 integrated 2000 in Lanzhou
metropolitan area, the basic pattern of land-use conversion was analyzed under the support of GIS. Secondly, according
to the data supplied by government from 1986 to 2000, we found out the driving factors of land-use conversion by using
principal component analysis and Granger causality test. Influence of the driving forces on land-use conversion was
estimated by using regression analysis method. Besides, from the views of market economy and government
intervention, the regulative mechanism of land-use conversion was analyzed theoretically. In the end, the paper presented
some feasible suggestions.