Abstract: Four aspects of soil deterioration in the tropical forest had been demonstrated according to experiment of the shifting cultivation on ecological efficiency of the semi-deciduous monsoonforest at Jianfengling,Hainan Island.With losing of the litterfall the supplemental source of the soil fertility and the hydrologic function are declined; soil and water erosion severe; the ability of water transportation and the storage capacity are decreased; soil fertility degraded owing to deterioration of the soil physico-chemical properties.It is suggested that the shifting cultivation system must be rid of practice establishing an agro-forest system based mainly on the woody plants,drawing up resonable overall and management for the tropical forest,preventing from slash-and-burn cultivation,carrying out of planting technique of ecology,so as to maintain the soil fertility and the protection of soil resource of the tropical forest.