Dynamics of water-high-viscosity ionic liquid ([BMIM] [PF6]) two-phase flow in a flow-focusing device were investigated by using a high-speed digital camera. Four flow regimes were identified: dripping, jetting, irregular and string of sausages. The rupture of the dispersed thread could be divided into the squeezing and the pinch-off stages. The complex wavy interfacial phenomena string of sausages were observed and highlighted. The size of the droplet and sausage were predicted respectively by a power-law function with the flow rate ratio and the capillary number.