Abstract: In this paper, we investigated the distribution of wild banana（M. itinerans） population and species composition within the population in Hainan Island, China. They mainly distributes in the region of latitude 18°45′~19°19′ north and longitude 109°22′~109°56′ east, and the majority of population distribution lies in the center and the east area of the island, which is in the 1800 mm isoline of annual rainfall. The wild banana is further proved as the species of Musa itinerans according to Simmonds taxonomy. Based on the factors of geomorphologic, landform, climate, vegetation and space, the distribution area of wild banana are zoned into Limuling, Fulongxiang, Nangaoling, Yinggeling, Baihualing, Atuoling, Dabenshan and Diaoluoshan units. About 28 species, including 4 trees, 5 shrubs, 8 herbaceous plants, 4 lianas and 7 ferns, were found within the investigated area of the Fulongxiang population. The results revealed that the singleness, symbiosis and competition to some extent among species existed within the population. Due to the human-disturbed and ecosystem stress, the germplasm resource of wild banana have been quickly lost and coevolution was changed. The germplasm resource protection of wild banana by in-situ and construction of modernized monitor system were proposed.