Abstract: Objective: To investigate the impact of CARE kV technology on radiation dose in coronary computed tomography angiography (CCTA). Methods: This retrospective study analyzed data from 1,529 patients who underwent CCTA at The First Affiliated Hospital of Chongqing Medical University between December 2023 and December 2024. All scans utilized CARE kV technology, with patients stratified by automatically selected kV values. Radiation dose metrics recorded included the volume CT dose index (CTDI_vol), dose-length product (DLP), size-specific dose estimate (SSDE), effective dose derived from DLP (ED_DLP), and Monte Carlo simulation-based effective dose (ED_Radimetrics). Dose ratio differences were characterized by SSDE/CTDIvol and ED_Radimetrics/ED_DLP. Group comparisons were conducted using Kruskal–Wallis H tests with Bonferroni correction, while associations between kV and dose metrics/ratios were assessed with Spearman correlation analysis. Results: Patients were categorized into four kV groups: 70kV (n=815), 80kV (n=541), 90kV (n=67), and 100kV (n=106). Significant intergroup differences (all P < 0.05) were observed in all dose metrics (CTDI_vol, DLP, SSDE, ED_DLP, ED_Radimetrics) and dose ratios (SSDE/CTDIvol, ED_Radimetrics/ED_DLP). Spearman analysis revealed moderate positive correlations between kV and CTDI_vol (ρ=0.52, P < 0.05), DLP (ρ=0.49, P < 0.05), SSDE (ρ=0.54, P < 0.05), ED_DLP (ρ=0.49, P < 0.05), and ED_Radimetrics (ρ=0.46, P < 0.05). A weak negative correlation was found between kV and SSDE/CTDI_vol (ρ=−0.30, P < 0.05), while a negligible positive correlation was observed between kV and ED_Radimetrics/ED_DLP (ρ=0.07, P < 0.05). Conclusion: CARE kV technology effectively reduces radiation dose in CCTA. All dosimetric metrics exhibit moderate positive correlations with kV, underscoring kV selection as a critical determinant of dose control. Conventional metrics CTDIvol and ED_DLP systematically underestimate actual radiation dose levels, with the extent of underestimation showing minimal dependence on the CARE kV-selected kV values. We recommend integrating SSDE and ED_Radimetrics into standardized dose management protocols to enhance patient-specific radiation protection and risk stratification.