When the switching frequency is above 100 kHz,the winding loss of the round wire magnetic component will increase sharply due to skin effect and proximity effect, which greatly limits its wide application. On the contrary, the planarmagnetic component can not only work at such high frequency,but also suitable for high power density applications for its lowprofile. However, in order to avoid core saturation and changethe inductance, the air gap is usually required in the design of theplanar magnetic component, which will produce fringing effectand further increase the winding loss. Based on Roshen's assumptions, this paper analyzes the planar magnetic component withcenter air gap. Firstly, the Schwartz-Christoffel mapping is usedto establish the mapping relationship between the air gap fringing region and the strip region. Then the magnetic field intensity incomplex form is obtained by the complex potential function andthe one in vector form is given, which is represented by the stripregion coordinate. Finally, the magnetic field intensity verificationand the thermal verification are carried out. The method pro-posed in this paper provides effective guidance for the design ofplanar magnetic components operating at high frequency.