Using the data of 11 climatic factors on 40 counties in the main producing areas of walnut of Yunnan Province, we analyze the impact of various climatic factors on the distribution of Yunnan walnut. The results show that Yunnan walnut has a great expectation on temperature and moisture. Temperature, including average temperature in January, average temperature in July, the average annual temperature and accumulated temperature≥10 ℃, has the greatest impact on the distribution of Yunnan walnut, and is the primary dominant factor; moisture, including annual rainfall and average relative humidity, has a great impact on the distribution of Yunnan walnut, and is the secondary dominant factor.