Abstract: In this paper, the Fujiwhara effect of binary cyclone and the characteristics of the track of cyclone after merging of the binary cyclone have been simulated and studied by using a nondivergent barotropic model. The experimental results show that the Fujiwhara effect can occur only when the initial separation distance between the two cyclones is less than the critical distance which depends on the structure of the cyclone and the relative intensity of the binary cyclone. The merging of binary cyclone, in fact, is the processes that one of them decays and vanishes while the other still maintains. In the case of consideration of βeffect, the resulting cyclone after merging of the two cyclones with the same intensity only drifts along straight line toward northwest, while it travels under the combined effect βdrift and the movement of a top when the two cyclones with the different intensity merge. These results obtained here are in many ways similar to behaviors of the interactions of binary typhoon in the actual atmosphere.