In the present review, recent progress on the vortex identification methods are introduced with a focus on the newly proposed omega method ( Ω method). The advantages of Ω method are summarized with many illustrating examples. Furthermore, comparing with other existing methods (e.g., Q criterion and λ2criterion), one of the characteristics of Ω method is its independence on the chosen threshold values for vortex identifications. The important parameters involved for the practical applications of Ω method are further discussed in detail together with the physical interpretation of the Ω and some suggestions of the future work. Other emerging topics (e.g., Lagrangian coherent structure and Rortex) are also introduced with comments.