Based on the climatic and topographic factors, an expert classifier is used to make an agroclimatic regionalization of Beijing Pear. The results indicate that the optimum planting areas of Beijing pear are around the retuse hills near Pinggu, Miyun, Huairou, Changping, Mengtougou and Fangshan. Compared with other classifiers, the expert classifier has significant advantage and practicabi lity in agroclimatic regionalization, since it makes full use of the experts' knowledge, experiences and the scientific researches in achieving an objective and comprehensive regionalization.