| El Nino, cause the anomaly equatorial Pacific sea surface temperature, impacts Ningxia temperature, precipitation and other elements which crops survival environment in the East Asian monsoon system through abnormal atmospheric circulation. In order to understand the effect of El Nino on change of climatic elements and yield in central and southern mountainous regions of Ningxia, the current study analyzed, by dynamic difference method, the climatic factors, agro-climatic resources, El Nino yearly occurrence，as well as the yield changes of wheat, maize and potato. The results showed that, El Nino causes a warm winter in Ningxia which facilities greenhouse agricultural production. El Nino makes warm winter and spring, but lowers temperature than normal in the summer significantly. It decreased thermal accumulation in crops during growing season, especially heat intensity highly insufficient in high altitude regions where maize cannot mature. In the following year of El Nino occurrence, the rainfall in spring increased in the central dry zone, which helps sowing and crop seedling growth, but decreased in summer and autumn which prone to drought. In southern mountainous region, El Nino caused more rainfall in the spring and autumn，but less in the summer, likely to cause drought in corn crucial growing stage. In the late filling and maturity, more precipitation may cause potato late blight and interrupt harvest. When El Nino occurs, the yields of winter wheat, corn and potato are decreased, but the yields of three crops are increased significantly in the following year in central and southern mountainous regions. |