In this paper, a magnetic integrated structure of CLLC resonant converter is proposed. The non-interleaved winding structure design is adopted, and the distance between the primary and secondary winding is increased as a control variable, which effectively increases the leakage inductance of the transformer. Only one magnetic core is used to realize the three magnetic components in the CLLC resonant tank, which solves the problem of too many magnetic components in the CLLC resonant converter. At the same time, the influence of the parasitic capacitance of the winding on the working characteristics of the CLLC resonant converter is introduced, and the factors that affect the parasitic capacitance of the winding are analyzed on this basis. Finally, an experimental prototype with 400V input, 40V~60V output, 1kW power rating and resonant frequency of 1MHz is designed. The experimental results verify the correctness and effectiveness of the proposed optimal design method for planar magnetic.