This study determines the feasibility and effectiveness of the media mobile application project-based learning on service company materials. This type of research is development research using the Borg and Gall product development model combined with the Dick and Carey design model. This research was conducted on Sei Suka Vocational High School, Batubara Regency. The method used in this research is a quasi-experimental method. The research sample of 62 students consisting of 31 students as an experimental class who was taught using media mobile application based on Project Based Learning and 31 students as a control class who was taught using conventional media. The results of the hypothesis test prove that there is a significant difference between the results of student Service Company Accounting material taught using the media Mobile Application based Project Based Learning and the results of Service Company Accounting used in conventional media. This is indicated by the data acquisition, namely t-stat was 4.43 while t-table was 1.67 and significant level of 0.05 through the interpolation of table was 1.63. We concluded that the effectiveness of media mobile application-based Project Based Learning with Service Company Accounting material is higher than using conventional media.