Abstract: This paper takes the scale of inbound tourism in Yunnan Province from 2006 to 2017 as the research object, using the theory of standard deviation, discrete coefficient, primacy degree and rank-size distribution to reveal the spatial-temporal differentiation characteristics of the scale of inbound tourism in Yunnan Province, using Pearson correlation coefficient and multiple linear regression method to explore the factors causing the difference of inbound tourism in Yunnan Province and the degree of influence, and constructing the grey prediction GM (1,1) model to measure the inbound tourism scale of each prefecture in the next six years. The results are as follows:（1）the scale of inbound tourism in Yunnan Province is unbalanced, the distribution of the first place is not obvious, but the relative difference is shrinking year by year, the degree of agglomeration and monopoly is declining, and the development of tourism tends to convergence.（2）compared with the capacity of tourism reception, the abundance of tourism resources is the main reason for the difference of inbound tourism scale in Yunnan Province.（3）Yunnan Province has great potential for inbound tourism development, and the competition among the first cities is more and more fierce. In the future, some middle cities will become new growth points of inbound tourism scale. It also puts forward corresponding suggestions for different inbound tourism development modes in cities, with a view to providing a theoretical reference for the development of inbound tourism in Yunnan Province.