Abstract: The temporal naked cropland is the main sources of the dust of Beijing area in winter and spring. While the timely and exact monitoring of the temporal naked cropland is important to make and realize the reconditioning plan. In this paper, based on the phenological feature difference of the crops planted in the temporal naked cropland and the other land cover types, 3 TM images of different time in spring and summer 2004 which cover Beijing area are selected. The PVI (Perpendicular Vegetation Index) are computed and used while the DEM (digital elevation model) and the vector of Beijing district boundary are adopted too. Based on the different phenological feature of different land cover, the expert models to monitor the naked cropland of Beijing area in winter and spring were built. The area of the temporal naked cropland which scatter mainly in Yanqing county, Miyun county, Shunyi district, Tongzhou district and Daxing district from winter 2003 to spring 2004 is 87362.57 hm² with the model provided in this paper. By the monitoring result, the measures were presented to prevent the temporal naked cropland.