Abstract: Based on climatic and agricultural data and with Kassam's method of agroecological divisioning, the potential productivity of rape crops at different ecological zones in mountainous regions of western Sichuan Basin are calculated. Integrated regression equations of light, temperature, water and rape yield are computerized, and affected coefficients of ecological factors on rape yield are calculated. It shows that the potential productivity of rape crops in these regions is 2.7-4.0 times higher than practical yield, and the affected coefficients of temperature and precipitation are significant. Low temperature and cloudy and rainy weather in early spring are also important limiting factors to rape yield. Measures for popularizing intermediate and late mature fine breeds of rape crops are put forward and have been verified by practical truth.