Abstract: In recent years, global warming leads to the increase of heat resources, the shift of agricultural climatic zones, and the lengthening of crop growing season. These phenomena make citrus often suffer the effects of high temperature heat damage and low temperature freezing damage. At present, the refined climatic zoning of cash crops mainly focuses on tomato, cotton and other crops, but there are few studies involving citrus. Therefore, suitability evaluation model is used to accurately and quantitatively regionalize citrus planting, and to provide a basis for scientific planting and rational distribution of citrus.Using the climate suitability function, the temperature, precipitation, sunshine and comprehensive suitability models of citrus growth period are established. With Anusplin software, the observations of 361 meteorological stations in southern citrus growing region in recent 60 years (1960-2019) are interpolated and the climate suitability is calculated. Then the natural breakpoint method is used to divide the citrus growing area into four levels. The spatial variation characteristics of climate resources and suitability in target area are compared and analyzed in three decades. The results show that most of the regions in target area meet the climatic resources required for the normal growth and development of citrus, and the suitability of temperature, precipitation and sunshine show obvious spatial heterogeneity. The temperature suitability increases from west to east, the precipitation suitability decreases from north to south, the spatial distribution of sunshine suitability is high in the east and low in the west. The suitability of citrus planting is divided into 4 grades: Unsuitability (0 < F_c ≤ 0.17), sub-suitability (0.17 < F_c ≤ 0.36), suitability (0.36 < F_c ≤ 0.48), and most suitability (0.48 < F_c ≤ 0.74). The most suitable areas are mainly in the eastern part of Sichuan, the southern part of Yunnan, the northwestern part of Chongqing, Guangxi and Hubei, and the northwestern part of Sichuan is the unsuitable area. Since 1990, the area of the most suitable planting area has decreased by about 29%, and the area of the unsuitable planting area has increased by 34%. The spatial distribution of high temperature and heat damage and low temperature freezing damage probability verify the accuracy of the zoning results, which can be used to guide and optimize citrus planting and production practice.Different varieties of citrus and site conditions lead to different climate suitability responses. Besides, climate change has obvious impacts on crop planting structure, physiological traits and yield. Therefore, climatic regionalization research on different varieties should be paid more attention especially considering the future climate change scenarios, so as to support the planting and production of citrus.