Abstract: Gansu Province is an important ecological barrier in northwest China. The study of spatial pattern of potential vegetation productivity has become basic work toward the ecological environment rehabilitation and reconstruction in arid and semiarid areas of northwest China. Data from some meteorological stations were used to build climate models, and regression trees were applied for estimating potential NDVI based on climate variables and training data of actual NDVI. Then, potential NPP of Gansu Province was simulated by using CASA model and potential NDVI data. On this basis, potential ecological carrying capacity of 14 municipalities in Gansu Province was estimated using the improved ecological footprint approach. Results indicated that potential NDVI and potential NPP decreased from southeast to northwest in Gansu Province. The average potential NDVI and potential NPP of Gansu Province were 0.277 and 272.315 g C·m^-2, respectively. The potential ecological carrying capacity per capita (PECC) of the 14 municipalities in Gansu Province presented a distribution pattern of “big at both ends (south and north) but small in the middle”. Gannan Prefecture had the largest PECC, which was 11.616 hm² per capita, while Jiayuguan City had the least PECC, with only 0.228 hm^2 per capita.