Practical methods of economics are shaped by its fundamental method. Epistemological foundations as part of the fundamental method, play a significant role in the applied method of economics. Mainstream economics is currently using the deductive hypothesis method as its main method and other methods are used as complement. Hypotheses are also derived largely from the theoretical legacy of economics. The findings of other disciplines and empirical observations are used as a refinement to basic theories. A critical study of these methods based on epistemological foundations suggests that the axiomatic method has the disadvantage of using uncertain premise in economics. The method of deductive hypotheses uses only probabilistic premise, and in that case, is limited to eliminating the sequence clause by experimental test. Islamic scholars use certain premises to eliminate these harms and use the disconfirming of sequence clause and confirming if clause in the method of exceptional deduction. Inductive method in this view can have three forms (incomplete induction, complete and with practical results) in Islamic economics and leaving it causes methodological problems. The interpretive method could be used in the study of human economic action and the recognition of political obstacles, and the critical method can play a significant role in the prescriptive and policy dimension of Islamic economics