The CFD software was employed to study the fluid flow characteristics and heat transfer enhancement in the helical coiled channel under the action of jet. The cross-section of the helical channel was circular and the dimensionless curvature and pitch of the helical channel were 0.061 and 0.121, respectively. The simulated results were in good agreement with the existing experimental data. The structure of composite vortices and its evolution process in the channel have been discussed. The effect of jet action on heat transfer enhancement was investigated in the range of incident angle ?=π/6–π/3 and jet velocity ratio ?j=3–6. The results show that in the initial stage of jet in the helical channel, the secondary vortices induced by centrifugal force were completely suppressed by impact of the jet. And another pair of vortices named as jet induced vortices emerged under the impact and entrainment of the jet, wherein the rotating direction was opposite to that of the vortices induced by the centrifugal force. With the flow development, the structure of the jet induced vortices changed from two vortices into one vortex, and then, gradually dissipated and disappeared. The heat transfer of fluid near the inner wall of helical channel was significantly enhanced by the jet action. As ? decreased or ?j value increased, the heat transfer enhancement effect was increased. In the studied range of ?j≥4, without considering the jet flow rate increase, the comprehensive heat transfer enhancement factor JF1 was between 1.26 and 1.67, while when the jet flow rate increase was considered, JF2 was in the range of 1.008~1.19.