The invention provides a method for designing a housing of an anti-condensation ring main unit by using a finite element model. The method comprises the steps of: S1, performing three-dimensional modeling on overall ring main unit equipment, wherein the model parameters comprise distances of front and back, left and right of the ring main unit and the housing, height of a top space, shape of vents, position distribution of the vents and top inclination angle of the housing; S2, importing the model into a CFX toolkit of ANSYS software and performing grid division; S3, setting the boundary condition of the model; S4, obtaining various data of the housing the ring main unit by analog computation; S5, judging whether the various data satisfies a predetermined condition; S6, if not satisfying, adjusting corresponding values of one or more model parameters, and returning to step S2; and S7, if satisfying, outputting the obtained various data. By adopting the method, modeling analysis is performed on humidity, temperature, air speed and the like inside the ring main unit, so that the formed ring main unit can fulfill the purposes of reducing condensation, reducing the occurrence rate of electric accidents and the like without adopting the anti-condensation measures in the prior art.