The problem of effusion in gas well bottom hole grows increasingly serious in the late exploitation of gas field. The technology of vortex drainage has good prospects because the tool is conveniently manufactured and environmentally friendly. Currently, the mechanism for the vortex drainage and the theory of fluid motion are still missing. Therefore, in order to further realize the flow field of bottom hole, verify drainage mechanism and optimize working conditions, the study established a three-dimensional structural model of vortex tools to simulate the progress of gas well drainage by using the CFD software Fluent. By monitoring the liquid content of wellhead, liquid’s radial distribution, observing the flowing state of gas-liquid and the path line, analyzes the influence of gas production rate, liquid producing capacity of wells and the main structure parameters of vortex tools (the length of the pitch of the helical blade and screw) on gas well flow field. The study revealed the working mechanism of vortex tools to facilitate the understanding of the nature of the vortex drainage process, guided the field how to select the preferred process conditions and provides the basis for optimizing the structure and provide theoretical basis for the application and the dynamic simulation of vortex drainage technology.