An optimizing design method for a chassis structure of electronic equipment is disclosed, including: investigating from the point of view of mechanical, electric and thermal three-field coupling, determining the preliminary design size of the chassis, performing a mechanical analysis by using a mechanical analysis software such as ANSYS; converting the mesh model among the three-fields, obtaining the mesh model used for the electromagnetic and thermal analyses; setting the thermal analysis parameters, performing the thermal analysis by using an electromagnetic analysis software such as ICEPAK; determining a resonance frequency of the chassis and an electric parameter of the absorbing material, performing an electromagnetic analysis by using a thermal analysis software such as FEKO; correcting the analysis result by sample testing; determining whether the chassis satisfies the design requirement, if it satisfies the requirement, the optimizing design will be finished, otherwise, modifying the preliminary computer assisted design model, the electromagnetic analysis parameter and the thermal analysis parameter, repeating the above processes until the requirement is satisfied.