The purposes of this research were : 1) to study of factors personal the Demonstration School of Ramkhamhaeng University 2) to study food buying through online applications 3) to study factors of marketing mix towards buying food through online applications 4) To study the relationship between personal factors to buy food through online applications of the Demonstration School of Ramkhamhaeng University and 5) to comparison of opinion toward marketing mix towards buying food through online applications by personal factors. The samples students are studying in high school of the Demonstration School of Ramkhamhaeng University and never buy food through the applications online of 226. The instruments used in research questionnaires and interviews. The statistics used for data analysis were frequency percentage mean standard deviation Chi-square values and One Way ANOVA. The results showed that: 1) Most students were male 18 years of age by studying high school grade 6 and receive money from their parents for about 201-300 baht per day. 2) Most students purchased food Skootar by a full set this was why they had ordered food restaurants and a variety of food items in order was to feeding each paid 200 baht the students were ordering food when a new food product the purchase of food for every taste while students can be taken food delivered within 31-60 minutes and the most important in the fresh new foods. 3) Analysis of the data on the opinion toward was marketing mix towards buying food through online applications of the Demonstration School of Ramkhamhaeng University found that overall; students have commented on the high level the first two items in order from most to least found the side with the highest mean score was the distribution the second was the price and the minimum personnel. 4) Relationships between personal factors as gender age education and the money received from parents to buy food through online applications of the Demonstration School of Ramkhamhaeng University found that was relationship the statistical significance level. 05. 5) Comparison of opinion toward marketing mix towards were buying food through an online application by personal factors were found Gender age education The money received from parents of different. Levels opinion toward marketing mix used to purchase food through an online application not different the statistical significance level. 05.