Abstract: Development Economics has experienced three stages during the half century since it was born: structuralism, neo-classical thinking and neo-classical political economics. Each stage is mutually independent in content and form. However, the relationship and internal logic of theoretical evolution have never been carefully discussed. The analysis only from the view of the relation of government and market, or from methodology, can only distinguish the theoretical system of the three stages but cannot reveal the internal connection of the three. This paper tries to understand and grasp the evolution of development economics from the point of "advantage of backwardness". In a sense, development economics is evolved with the deepening of the understanding of developing countries' advantage as later-comers.