NOAA-AVHRR data have been more and more used by scientists because of its short temporal resolution, large scope, inexpensive cost and broad wave bands. On macro and middle scale of vegetation remote sensing, NOAA-AVHRR possesses an advantage when compared with other satellites. However, because NOAA-AVHRR also possesses problem of low resolution, data distortion and geometrical distortion, in the area of application of NOAA-AVHRR in large scale vegetation-mapping, the accuracy of vegetation classification should be improved. This paper discuss the feasibility of integrating the geographic data in GIS (Geographical Information System) and remotely sensed data in GIS. Under the environment of GIS, temperature, precipitation and elevation, which serve as main factors affecting vegetation growth, were processed by a mathematical model and qualified into geographic image under a certain grid system. The geographic image were overlaid to the NOAA-AVHRR data which had been compressed and processed. In order to evaluate the usefulness of geographic data for vegetation classification, the area under study was digitally classified by two groups of interpreter: the proposed methodology using maximum likelihood classification assisted by the geographic database and a conventional maximum likelihood classification only. Both result were compared using Kappa statistics. The indices to both the proposed and the conventional digital classification methodology were 0.668 (very good) and 0.563 (good), respectively. The geographic database rendered an improvement over the conventional digital classification. Furthermore, in this study, some problems related to multi-sources data integration are also discussed.