Ethnobotanical surveys for traditional knowledge of Colocasia gigantea （Blume） Hook. f. eaten by 11 nationalities in 24 villages of southwestern Hu’nan， Guangxi， Yunnan and Guizhou were conducted by semi-structured interview， key informant interview and participatory survey， the traditional knowledges such as field identification characteristics， edible parts and methods, and local names were recorded， and the possible toxic mechanism of wild C. gigantea was discussed according to related literatures. The results show that C. gigantea has similar morphological characteristics with Alocasia macrorrhizos （Linn.） G. Don belonging to the same family. People distinguish C. gigantea according to characteristic of “petiole with white powder”. Affected by regions， the name of C. gigantea called by different nations is not consistent， and they always name it according to its external characteristics and geographical name. C. gigantea is mainly used as edible vegetables， and edible parts are mainly petiole. In addition， it has medicinal and ornamental value. At present， the number of wild resources of C. gigantea is significantly reduced， and its cultivated area also shows a decreasing trend. According to survey results， some suggestions are put forward for cultivation， research and development of C. gigantea.