Background The base frame provides stable support for the helix, antihelix, and tragus-antitragus complex in microtia reconstruction, and this support is vital to attain a highly defined outline for a reconstructed auricle. The success of base frame sculpting depends on appropriate treatment of the cartilage, mainly the sixth and seventh costal cartilages, which may have different characteristics. The aim of this study is to demonstrate the relevant details for base frame fabrication in various scenarios.Methods This study included 352 patients with microtia who underwent autologous auricular reconstruction between 2016 and 2019. Concerning the different sizes and characteristics of the costal cartilage used for base frame reconstruction, we describe related methods for fabrication and introduce corresponding strategies for proper management.Results Relevant techniques in base frame fabrication have been shown to produce favorable results. The elaborately sculpted base frame establishes a stable foundation and natural protrusion of the helix, antihelix and tragus-antitragus complex. The base frame contributes to the integrity of a harmonious appearance of the reconstructed ear.Conclusions The elaborate design and appropriate utilization of costal cartilage for base frame sculpting is one of the most significant and fundamental processes in microtia reconstruction. It contributes to achieving a clearly defined outline of the auricle with harmonious integrity, which is as important as the other projected subunits.