An electrospun composite fiber process is a multi phase and multi physics process. It was very difficult to study a chargedjet in the electrospinning process for the fabrication of composite fibers by experiments. In this study, the liquid-solid two-phase flow in the electrospinning process for fabrication of composite fibers was researched numerically. The results showed the addition of conductive nanoparticles resulted in the increase of the jet flow velocity, and the decrease of the fiber's diameter. The CFD results corresponded well with the experimental data.