Under the new energy convergence of the new power system, the harmonic content of the converter station increases, and the dry-type air-core smoothing reactor will face more complex operating conditions, and the entrapped winding electrodynamic force caused by it will be an important cause of the reactor failure. This paper analyzes the harmonic characteristics of the valve side of the converter station under the new energy collection of the new power system, and studies the electrodynamic distribution characteristics of the encapsulation winding of the dry-type air-core smoothing reactor under the condition of DC and multiple harmonic superposition. Firstly, based on Fourier analysis, the harmonic characteristics of dry-type air-core smoothing reactor in operation are obtained.Then the mathematical model of the reactor is established, and the electrodynamic distribution characteristics under different operating conditions are studied by the finite element analysis method of field-circuit coupling.The research shows the superposition of multiple harmonics makes the magnetic field and electrodynamic force of the reactor winding unevenly distributed, and the radial electrodynamic force of a layer is significantly higher than that of the adjacent layer winding. Under the action of alternating magnetic field, the overall radial electric force of the reactor increases by 3 times, and the axial electric force increases by 4 times. The above research results can provide reference for insulation fault analysis.