Trust network is an effective means of resisting malicious fraud and reducing the risk of interactions between users. Most of existing researches focus on trust propagation and aggregation strategies, while pay little attention to the importance of agents. This paper presents a sequential pattern mining algorithm which called T-Seq, in which trust propagation process is regarded as trust sequences. It is effective in important nodes discovery through sequences mining. Experiments showed the effectiveness of T-Seq in sequential pattern mining and important nodes discovery.