The considerable increase of mobile device users in recent years causes a strong demand on secured wireless bank services and reliable mobile commerce (m-commerce) applications. Since mobile payment (m-payment) and banking is a critical part of most wireless information services and mobile commerce applications, how to build secured m-payment systems becomes a research hotspot. This paper presents an effective Mobile Payment System (MPS) in existing wireless insecure environments using mobile devices. The proposed framework provides a secure and convenient payment mechanism.