Background To investigate the application value of ultrasound in assessing the short-term impact of sleeve gastrectomy (SG) on common carotid artery (CCA) structure and lower limb arterial hemodynamics in patients with metabolic syndrome (MS). Methods Twenty-one patients with MS undergoing SG at our hospital were enrolled as the experimental group, with 29 healthy volunteers as the control group. Ultrasound was employed to measure and compare the lumen diameter (D), adventitial thickness (AT), intima media thickness (IMT), peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI) of bilateral CCA as well as the PSV and early diastolic reverse flow velocity (R) of lower limb arteries including common femoral (CFA), proximal superficial femoral (SFA), middle superficial femoral and popliteal arteries (POA) at baseline and 1 month after SG. The correlation between laboratory indicators and ultrasound parameters of CCA was analyzed. Results The MS group had higher D (P = 0.004 and 0.041, respectively), AT (both P = 0.00), and IMT (both P = 0.00) of right and left CCA, lower EDV of right and left CCA(P = 0.009 and 0.019, respectively), lower PSV of RCCA (P = 0.021) and ultrasound parameters of lower limb arteries at baseline, compared to the control group. One month after SG, the MS group exhibited lower AT (both P = 0.00), IMT (P = 0.001 and 0.00, respectively), PSV and EDV (P = 0.009 and 0.019; P = 0.018 and 0.008, respectively)of right and left CCA, lower D of right CCA (P = 0.030) and certain lower limb arteries compared to preoperative levels. Correlation analysis revealed a positive correlation between white blood cell count (WBC), red blood cell count (RBC), hematocrit (HCT), absolute neutrophil count (NC), monocyte percentage (MP), average glucose (eAG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C), and ultrasound parameters of CCA (P < 0.05). Conclusion Patients with MS exhibited significant improvements in partial ultrasound parameters of CCA and lower limb hemodynamic 1 month after SG, with a significant correlation to laboratory indicators, suggesting that ultrasound can offer clinical application value in assessing postoperative changes following SG in patients with MS and validating the effectiveness of SG.