Abstract: objective To explore the correlation between ultrasound measurement of the inferior vena cava and internal jugular vein collapse index and the occurrence of hypotension in patients with gastrointestinal surgery after general anesthesia, and analyze the predictive value. Methods A total of 112 patients undergoing elective gastrointestinal surgery under general anesthesia were recruited. The patients were 45-60 years old, ASA I-III grade, and BMI 18-24 kg/cm2. The mean arterial pressure (MAP) and baseline blood pressure were recorded before operation, portable ultrasound was used to measure the maximum and minimum internal diameters of the internal jugular vein (IJV) and inferior vena cava (IVC), the internal jugular vein collapse index (IJVCI) and the inferior vena cava collapse index (IVCCI) were calculated before the induction of anesthesia. After anesthesia induction, blood pressure was recorded every 1 minute before operation. Hypotension was defined as greater than 20% decrease in MAP from baseline or MAP less than 60 mmHg. The correlation between each measurement index and hypotension after induction of anesthesia was calculated, and the sensitivity, specificity of IJVCI and IVCCI in predicting the occurrence of hypotension after induction of general anesthesia were analyzed through drawing receiver characteristic curve (ROC) of related indicators. Results Among 112 patients, 47 had hypotension after induction of anesthesia, accounting for 42%, and 58% of them had no hypotension. Before and after using vasoactive drugs or supplementing volume, the percentage of decrease in MAP is significantly positively correlated with IJVCI and IVCCI, and the correlation coefficients were 0.81 (P<0.001) and 0.85 (P<0.001), respectively. For predicting hypotension, With 40.04% as the cut-off value of IJVCI, the area under the curve (AUC) is 0.84 (0.75~0.92), the sensitivity is 70.2%, and the specificity is 89.2%. With 39.34% as the cut-off value of IVCCI, the area under the curve (AUC) It is 0.85 (0.77~0.93), the sensitivity is 68.1%, and the specificity is 90.8%. Conclusion Both IJVCCI and IVCCI are significantly correlated with hypotension after induction and can predict the occurrence of hypotension after induction of anesthesia. Both have similar predictive effects and are beneficial to the prevention of intraoperative hypotension