Abstract: To investigate the dynamic characteristics of fluid inside a conical plug valve and to optimize the valve structure, this paper used the open-source software OpenFOAM based on the k-\varepsilon turbulence model and the PIMPLE algorithm. The study simulated and analyzed the flow performance of the conical plug valve under different openings and different valve core fillet radii. The variation of fluid velocity, pressure drop, streamlines, flow coefficient, and resistance coefficient during the valve core closing process as the rotation angle increased were investigated, and relevant curves were plotted. The changes in fluid velocity and flow coefficient curves under different fillet radii were analyzed. The results showed that as the rotation angle of the plug valve increased, the pressure difference before and after the valve increased, resulting in greater flow loss. The flow coefficient decreased with the increase of the valve opening and increased with the increase of the valve core fillet radius at the same opening, which can provide a reference for the optimization of the conical plug valve structure.