Nowadays,more than 50%of the world population live in middle-income economies.Economies in the middle-income development stage are confronted with a number of challenges,such as economic restructuring,industrial upgrade and income growth.Therefore,academia around the world have paid much attention to theoretical and empirical researches of the "middle income trap " and long-term trends of global economic growth.Based on analyses about the long-term growth path of the world economy and the characteristics of different stages of economic development,this paper defines the "middle income trap" and its characteristics and examines,through a large number of cases from different economies,the reasons why "growth slowdown " arises during the middle-income development stage.These theoretic and empirical researches have reference value and heuristic meaning for China to actively respond to the challenges of the "middle income trap ".