The research aims to figure out students' epistemological belief shift about mathematics after having attended a lecture in a Polytechnic. In addition, it also aims to find out the relationship between their beliefs and mathematics performance. The study applied mix method with explanatory sequential design approach by conducting first study quantitatively and further study qualitatively. The sample consists of 223 participants drawn randomly by stratified random sampling method. The result showed that students' epistemological belief about mathematics either pre­ college or in-college period in Polytechnic was "poorly positive". Most of them (about 95%) had their epistemological beliefs about mathematics shifted with the changes "low increasing". Also, the belief shifting was positively correlated with mathematics performance at a significance level of 1%, and the Pearson correlation coefficient was 0.204. Some factors that affects students' epistemological belief about Mathematics shifted was: student's orientation purpose, assessment system, curriculum, methods of learning, and met-before.