To study the influence of a helical wire coil on the convective heat transfer capacity of the cylindrical cooling tube, then to obtain the enhanced cooling characteristics, a comparative analysis is performed between the cases with and without the wire coil based on finite element analysis. In particular, a specific model of the cooling tube with both the smooth inner wall areas and helical wire coil area is established. By comparing the flow velocities, fluid pressures, and convective heat transfer coefficients, etc., the significant effect of a helical wire coil on improving the convective heat transfer capacity is explained quantitatively. In addition, the enhanced cooling mechanism can be described in three points, i.e., increasing the thermal contact area, thinning or destroying the boundary layer, and promoting the formation of turbulence.