As we know, knowledge and parents social economics background influence the consumption behaviour of students. The knowledge of Islamic Economics students and Economics Science students has the differences, because their concepts of studying are differents too. Meanwhile, the variance of the parents’s job, money for their living cost, and the parents economics education also can give another influence to them in daily life, especially in consumption behaviour. The purpose of this research is to know how big the influence of student knowledge and parents social economics background to consumption behaviour, study on student of Islamic Economics FIAI and Economics Science FE UII. More over, the other purpose is to know whether there is any differences on consumption behaviour in those between. This research is done by doing the questionnaries, observations, and documentaries. The data analysis techniques used were quantitative measures, double linear regression and Mann-Whitney.Based on the research, the result are: 1) t Test (partially), the students knowledge doesn’t have any significant effect towards consumption behaviour, it’s shown by the value of t-measure is less than t-table: 1,158 < 1,996. While, the parents social economics background has 4,495 for the t-measure and  it has significant effect towards cosumption behaviour. 2) F Test (simultaneously) those two independent variables have a significant influence simultaneouslybecause the F-measure is more than F-table, 10,331 > 3,98. 3) Mann-Whitney Test, there is a difference on consumption behaviour between in students of Islamic Economics and Economics Science, it’s shown by the value of probability which is less than aplha’s, 0,001 < 0,05. 
Keywords: Consumption Behaviour, Knowledge, Social Economics Background