Advances in wireless network technology and the continuously increasing users of Personal Trusted Device (PTD) make the latter an ideal channel for offering personalized services to mobile users. However, the current mobile transactions are not provided with the non-repudiated characteristics. In this paper, we propose a novel scheme in self-service store. We involve an “observer” to coordinate the transaction to overcome the computing resource weakness of the PTD. This research integrates some cryptology such as public key infrastructure, hashing chain and digital signature and so on. The proposed protocol meets the self-service store requirements such that fairness, non-repudiation, anonymity, efficient verification, simplicity and practicability issues can be guaranteed. On the basis of the PTD is more portable and personal than personal computer, it will be expected the more widely use in PTD applications. Our scheme will facilitate the mobile commerce prosperously, and will bring more commerce profits and more convenient to mobile user in our daily life.