This research is attempting to probe into the language vitality of the Western Ali Tribe and Jilu Tribe in Pingtung County which by means of in-depth interview and questionnaire to understand the research question as the subsequently. (1) Understanding the usage of Western Rukai language through questionnaire; (2) Investigating the loss condition of Western Rukai language by in-depth interview with the leader of Western Rukai tribe; (3) Utilizing Landweer's Indicators of Ethnolinguistic Vitality to explore the current condition which the Ali tribe and Jilu tribe had undergone the typhoon and relocation catastrophe. The research outcome has demonstrated that the language vitality is highly related to one's residence, it is obvious that the villager who has lived in the permanent house can have better learning Western Rukai language condition. As a consequent, we should encounter this issue seriously to protect invaluable culture heritage.