The purpose of this study was to investigate the frequency of three commonly used treatments for skeletal class III malocclusion with maxillary transverse deficiency (MTD) (SCM) patients in East Asian, to find a quantitative method for precise discrepancy evaluation, and to find other potential indicators for treatment selection. A total of 239 adult SCM patients were divided into3 groups according to treatments.Dentofacial features were measured and the initial skeletal discrepancy was evaluated with computer-aided surgical simulation (CASS). Relationship between the degree of skeletal transverse discrepancy (STD) and other dentofacial features were analyzed by Spearman's rank correlation. The STD in East Asian could be quantitatively grouped as: mild (<4 mm), moderate (4-8 mm), and severe (>8 mm). Most patients (81%) could be diagnosed with mild STD, and were treated without surgical expansion. The upper first molars inclination, the required relative movement and the required maxillary movement were correlated to the degree of STD. The conventional orthodontic and orthognathic treatment without surgical expansion is the most frequent choice for East Asian SCM adults. CASS facilitated analysis is useful in an accurate MTD evaluation. Some dentofacial features were closely correlated to STD, and thus were helpful for the treatment selection.