This study aims to evaluate the utility of gastric ultrasound in assessing gastric emptying dysfunction in patients with hepatitis B cirrhosis and its correlation with alterations in portal venous flow and liver stiffness. Gastric motility and emptying parameters, portal venous flow parameters, and liver stiffness were measured by ultrasound in 42 patients with hepatitis B cirrhosis and 48 healthy controls. Statistical analysis was performed to compare the differences in these parameters between the two groups and to analyze the correlation between gastric ultrasound parameters and alternations in portal venous blood flow and liver stiffness. Firstly, the Gastric Motility Index was significantly lower in the experimental group than in the control group, while other gastric ultrasound parameters were significantly higher (p < 0.01). Secondly, measurements obtained from two-dimensional ultrasound, Color Doppler Flow Imaging, and two-dimensional Shear Wave Elastography revealed that Portal Vein Diameter (PVD) and Liver Stiffness (LS) were significantly higher in the experimental group compared to the control group, while the maximum portal vein velocity (PVmax) was significantly lower (p < 0.01). Finally, correlation analysis demonstrated that gastric ultrasound parameters correlated with PVD, PVmax, and LS. Gastric function is significantly impaired in patients with hepatitis B cirrhosis compared to controls, and gastric ultrasound parameters demonstrate a notable correlation with PVD, PVmax, and LS. Gastric ultrasound effectively evaluates gastric motility and emptying function in these patients, offering a reliable foundation for clinical diagnosis and management.