Abstract:Being an important subtropical fruit tree, longan is sensitive to temperature change. Selecting 60 counties in South China area and using the temperature suitability model, the article calculates the temperature suitability of longan, evaluates the temporal and spatial differences and also predicts the temperature suitability of longan. Firstly, the article analyzes the temperature suitability of longan at different growth stages. The result shows that temperature change has a great impact on the temperature suitability of dormancy stage, physiologic differentiation of flower bud stage and morphologic differentiation of flower bud stage, all of which have low suitability and high variability. On the contrary, the other three stages have high suitability and low variability. This is caused by the temperature differences between the different growth stages. It is hot damage in winter and spring rather than cold damage that plays an important role in longan production in South China area by further study. Secondly, the article analyzes the suitability in terms of average temperature of the 60 counties, the result shows that the temperature suitability increases with increasing latitude in South China area, based on the relationship between yield reduction rate and the temperature suitability degree, the article divides South China area into five types: the high suitability type, whose value is higher than 0.80; the suitability type, whose value ranges from 0.75 to 0.80; the medium suitability type, whose value ranges from 0.65 to 0.75; the low suitability type, whose value ranges from 0.55 to 0.65; the no suitability type, whose value is lower than 0.55. Finally, the article analyzes the inter-annual change of temperature suitability at different growth stages, and the result shows all the growth stages except for fruit growth and maturity stage and treetop growth stage have a decreasing trend in the future. At the same time it analyzes the temperature suitability change trend of the 60 counties, and finds that these places also have a decreasing trend except for the part area of Fujian Province and there exists difference among them, also the suitability region will be possibility extending to the north zone in the future. Similarly based on the temperature suitability over 10 years change trend of the 60 counties, the article divides South China area into four suitability change trend types: the high-decrease type, whose value is lower than -0.01; the medium-decrease type, whose value ranges from -0.005 to -0.01; the low-decrease type, whose value ranges from -0.005 to 0; the increase type, whose value ranges from 0 to 0.01.