This research is a survey research. With the purpose to study the decision making behavior to buy cosmetics direct sales system of undergraduate students. Using the questionnaire as a tool to collect information. By way of a random sample from the formula of Taro Yamane number of 381 people. The statistics used in data analysis, percentage, mean, standard deviation, and Chi-square Test. An analysis of the data showed that. Most of the respondents are female. Revenue 6001-8000 baht per month. The buying behavior of cosmetics. Mainly to buy cosmetics brand marketing Mistine most. Makeup Products category. From a cosmetic shop. The decision to buy cosmetics Direct selling system. Mainly to strengthen the personality. And the reason for the decision to add beauty, Purchase cosmetics used around towns