BACKGROUND: H-type hypertension is associated with an increased risk of cognitive impairment, but the relationship between muscle ultrasound parameters and cognitive function in this population remains unclear. This cross-sectional study investigated the association between muscle ultrasound parameters and cognitive function in patients with H-type hypertension and sought to identify ultrasound parameters associated with cognitive status. METHODS: This cross-sectional study included 125 patients with H-type hypertension. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). Participants were classified into non-cognitive impairment (n = 68) and cognitive impairment (n = 57) groups. Muscle thickness (MT), muscle cross-sectional area (MCSA), shear wave velocity (SWV), and pennation angle (PA) were measured at selected upper- and lower-limb muscles. Partial correlation analysis, multivariable linear regression, and binary logistic regression were performed to examine associations between ultrasound parameters and cognitive status. RESULTS: Compared with the non-cognitive impairment group, the cognitive impairment group had significantly lower MT and MCSA at multiple sites, including the biceps brachii, brachioradialis, rectus femoris, and lateral gastrocnemius (all P < 0.05), whereas SWV and PA did not differ significantly. After adjustment, rectus femoris MT showed the strongest correlation with total MoCA score (r = 0.470, P < 0.001). Rectus femoris MT remained independently associated with total MoCA score (B = 0.509, 95% CI: 0.330-0.688, P < 0.001) and cognitive impairment (OR = 0.811, 95% CI: 0.706-0.933, P = 0.003). CONCLUSION: Reduced rectus femoris MT is independently associated with poorer cognitive function and the presence of cognitive impairment in patients with H-type hypertension. Rectus femoris MT may serve as a useful adjunctive ultrasound marker of concurrent cognitive status, but prospective studies are needed to determine its clinical utility.