Abstract: The small scale swirl-vane steam separator was built and studied by experimental and numerical methods using air-water modeling fluid. The experimental results show that the separation efficiency is mainly influenced by water flow rate. It increases gradually with water flow rate. The increase tendency declines when the water flow rate is larger than 0.3 m³/h, and furthermore it decreases. The pressure drop is sensitive to air flow rate and increases markedly with air flow rate. The numerical analysis model was established for swirl-vane steam separator using Euler two-fluid model. The gas was defined as continuous fluid while water was defined as dispersed fluid, and Reynolds stress model (RSM) was used to solve the turbulent stress. The impact of droplet size on the separation characteristics was analyzed in this simulation. The simulation results show that the droplet size distribution has a marked influence on the separation efficiency, and the existences of the micro water particles cause the marked reduction of the separation efficiency of swirl-vane steam separator.