The increased usage of mobile phones and the user’s interest for using phones for mobile commerce application has lead to an urge for strict security authentication of the users. The password based authentication is becoming insane as there are many passwords too very simple. The biometric based authentication systems are becoming common place and are used widely as it is more stable and unique. The researchers are developing more and more fuzzy logic based multi-modal biometric authentication systems to verify the identity of the mobile phone users. This article presents one such authentication work that involves three parts of work. First part deals with the study of various models of mobile commerce authentication in a number of multi-model biometric authentication levels are defined to balance between the usability and security. Second part is a study of a multi-model biometric authentication system involving typing behavior recognition; face recognition and speaker recognition techniques to establish the identity of the user of mobile phone using m-commerce in it. Finally the fuzzy logic model proposed is studied to find out the transaction risk in m-commerce as there are some issues in the deterministic biometric authentication system.