This study aims to determine the effect of shopee big sale advertisements on purchasing decisions with consumer attitudes as an intervening variable (Survey of Shopee Users at Muhammadiyah University of Purwokerto). 130 respondents using the Structural Equation Model (SEM) technique. The research instrument uses a questionnaire, data analysis uses PLS and group statistics. The results of the study show that there is an influence between advertising and purchasing decisions, there is an influence between advertising and consumer attitudes, there is an influence between consumer attitudes and purchasing decisions, and there is a difference between purchasing decisions and gender with a ratio of 79 female students and 51 male students.