A multi-user shared mobile payment protocol based on group signature is proposed. In order to solve the problem of limited resources such as computing power and storage space of mobile devices, a group signature algorithm with a shorter signature length is adopted. And smart phone is used as mobile payment proxy for smart devices. For user privacy protection, anonymous mobile payment and device use among family members are realized. This protocol uses group signatures and challenge-response based secure mutual identity authentication to resist parallel sessions, replay, man-in-the-middle, denial of service and other attacks in the network. Moreover, the complexity of protocol interactions of mobile payment and device use is reduced from O(n) to O(1). Finally, the indistinguishability game proof and analysis show that the proposed protocol in this paper can realize the anonymity of family members and meet the security requirements of the system, such as mutual identity authentication and traceability, and has certain application prospects in the smart home market.