This study aimed to analyze the level of religiosity and the Effect of Knowledge Level Islamic Bank on students’ interest in becoming a customer of Bank Syariah. Subjects of this study are students of senior high school in Yogyakarta. The schools are SMA MAN 1 Yogyakarta, SMA Muhammadiyah 3, and SMA Negeri 5 Yogyakarta. In this study, the researcher selected sample of 139 responses by using purposive sampling method .The analytical tool that used by researcher is SPSS version 15. The data were analyzed using multiple linear regression models. Based on the data that has been done showed by researcher. The level of religiosity in becoming customers of Islamic banks is significant positive effect on students' interest that proved by sig 0.000 < α (0.05) and the direction of positive regression coefficient 0.328. Besides that, the level of students' knowledge of Islamic banks is significant positive effect on customer interest into Islamic banks proved with sig 0.000 <α (0.05) and the direction of positive regression coefficient 0,400.