隨著資訊時代來臨、社群媒體普及，現今的消費者有能力從網路尋找多元的資訊進行購買決策，消費者也能互相交換資訊。YouTube的時尚美妝影片數量多、內容豐富，消費者在尋找產品或使用教學的影片時，會將其作為搜尋來源之一，並相信這些內容不具商業利益，客觀且公正。 美妝YouTuber樂於創作影音內容，分享產品資訊、購物經驗、和生活事物等議題，進而培養出一群訂閱的觀眾，成為具社群影響力的網路名人；然而這些YouTuber如何影響消費者、為何能吸引特定族群的消費者，目前國內外相關的研究仍十分稀少。 本研究以美妝影音部落格和美妝消費者為研究對象，探討「美妝消費者的購買決策過程，及其如何受到YouTuber之影響」，採用質性的網路民族誌 (netnography) 作為研究方法，先搜集三個YouTube熱門美妝頻道的網路資料，參與留言區的討論，再訪談十六位千禧世代的美妝消費者。本研究發現：一、創作者和觀看者透過YouTube凝聚成美妝「社群」；二、美妝YouTuber具備「發起者」和「影響者」的角色；三、美妝消費者的行為和態度可能受到人氣YouTuber影響。 / Nowadays, consumers search information about products, prices and distribution on the Internet before their purchase decisions so that social media has radically changed the communication landscape. Consumers are able to share their purchase experiences online and interact with other users. More and more users are using YouTube as a search engine as well as looking for makeup tips, tutorials, and product recommendations because consumers would believe these user-generated contents are reliable and trustable. The aim of this research is to explore how YouTubers of beauty industry in Taiwan, have influenced their viewers and to what extent this influence on the purchase decision process. This study uses a qualitative approach ‘netnography’ as the main research methods to collect data. Three YouTube beauty channels were observed and participated; additionally, 16 in-depth interviews with millennial consumers were conducted. The research finds out that YouTube beauty channels can be seen as communities where relationships between YouTubers and viewers is formed. YouTubers are the initiator and influncer on the purchase decision journey. The study also found that the popularity of YouTuber may affect consumers’ behaviors and attitudes.