To the public, aboriginal peoples' legitimacy for co-management of the land partly comes from traditions passed down through history. In the past, traditional ecological knowledge (TEK) was transmitted by oral history, fables, and ceremonies, instead of being written down and documented. The purpose of this study was to discover existing contents and influencing factors of theoretical and practical TEK. Questionnaires were used to investigate the Paiwan people who live in Jialan Village, Jinfeng Township, Taitung County. Results showed that respondents had mediumgrade theoretical TEK. However, this cognitive ability was not homogeneous across individuals. Gender and other socioeconomic factors had a significant influence on awareness of theoretical TEK. It was noteworthy that the respondents' awareness level of theoretical TEK increased with age. As for practical TEK, although the study area is near forests, about 30% of the respondents used neither plants nor animals. According to the use and collection frequencies, it is clear that these aborigines no longer wholly depend on natural resources for their daily lives. Socioeconomic factors also rarely influenced respondents' practical TEK. Finally, we found a positive and statistically significant correlation between the theoretical TEK of plants and the plants used in line with theoretical expectations.