Background: Left-ventricular (LV) characteristic measurements are crucial for evaluating the feasibility of biventricular repair (BiVR). This study aimed to determine the threshold of LV quality on cardiac computed tomography (CCT) for BiVR in children with a dominant right ventricle (DRV). Methods: We retrospectively reviewed all children with a DRV who underwent either BiVR or single ventricle palliation (SVP) at our institution between 2003 and 2019 in a case-control study with healthy individuals. Measurements including LV end-diastolic volume (LVEDV, mL), LV myocardial mass (LVMM, gm), and mitral annulus area (MAA, cm{}^2) were quantified using CCT. The factor with the highest correlation with body size was used to adjust these three measurements to derive normal references in the control group. The LV quality of patients on each CCT measurement was represented as a percentage of the normal reference data that we established. The feasible LV quality for BiVR was defined as the lowest limit of all three LV measurements in one subject who survived BiVR among our patients with DRVs. Results: The cohort comprised 30 patients and 76 healthy controls. Height was the factor with the highest correlation with all three LV measurements. Height-adjusted normal reference curves and formulas were created. The mean LV quality in surviving patients who underwent BiVR was better than that in those who underwent SVP. The lowest limits for LV quality in one survivor of BiVR were 39.1% LVEDV, 49.0% LVMM, and 44.9% MAA. During follow up, the LV quality of patients who received BiVR shifted to the normal range. Conclusions: LV quality should be at least greater than 45% of normal values to promise survival in patients with DRVs who are being considered for a BiVR.