This paper attempted to use the online-based semantic annotation tools Wmatrix to retrieve and identify the metaphors in a self-constructed corpus. Results show that the thematic analysis and comprehensive screening function of Wmatrix can help break the existed or presupposed limit of researchers. Therefore, it can help the reader get access to the source domain as well as the corresponding word list to the largest scale. Besides, as one of its contributions, Wmatrix can provide new research train of thoughts in terms of metaphors at the concept level. In addition, online annotation tools are supposed to be widely applied in future research.