Research on model of population flow in the undeveloped city of China´s

There is a limit when the Todaro Model is used to population flow in Chinese undeveloped city. This paper begins with the real fact of China, combine the advantages and disadvantages of classic model which of home and abroad. We research the population flow in Chinese undeveloped city with the combination of Todaro model and P-N junction model. At last, we text the new constructed model with the data of population flow from Yunnan province, then have a conclusion.