Objective To observe the changes of blood oxygen and pressure in sacral compression part of patients with gynecological malignant tumor undergoing lithotomy position, and analyze the correlation between the two and intraoperative pressure injury. Methods A total of 216 patients with gynecological malignant tumor who underwent lithotomy from October 2020 to October 2022 in our hospital were prospectively selected. Blood oxygen and pressure in the sacrococcygeal compression part were measured at the time of admission and at the end of the operation, and the changes were observed. The incidence of pressure injury in patients with gynecological malignant tumor at lithotomy position within 3d after operation was counted and divided into injury group and non-injury group. The clinical data of the two groups were compared, and the correlation between blood oxygen and pressure at sacral compression part and pressure injury during 〖HJ48x〗operation was analyzed. Results At the end of the surgery, the blood oxygen in the sacral compression part of patients undergoing lithotomy position for gynecological malignant tumor was lower than that at the time of admission, and the pressure was higher than that at the time of admission (t=17.475 and 15.690, P<0.05). Among 216 cases of gynecological malignant tumor treated with lithotomy position, 21 cases (9.72%) suffered from intraoperative pressure injury. On admission, the blood oxygen level in sacral compression part of the injured group was lower than that of the intact group, and the pressure was higher than that of the intact group (t=3.930 and 5.227, P<0.05). The results of the two-point correlation analysis showed that blood oxygen in the sacral compression part of patients with gynecological malignant tumor undergoing lithotomy had a negative correlation with intraoperative pressure injury (r=-0.252,P<0.05), and the pressure in the sacral compression part had a positive correlation with intraoperative pressure injury (r=0.336, P<0.05). Logistic regression analysis showed that blood oxygen in the sacral compression part was a protective factor for intraoperative pressure injury in patients undergoing lithotomy position for gynecological malignant tumors (OR=0.458,P<0.05). Pressure at sacral compression site was a risk factor (OR=1.412, P<0.05); The ROC curve was drawn, and the results showed that oxygen and pressure in the sacral compression site had certain predictive value in predicting AUC=0.753 and 0.805 of intraoperative pressure injury in patients undergoing lithotomy position for gynecological malignant tumor, and the combination of the two had higher predictive value (AUC=0.862). Conclusion Blood oxygen in sacral compression decreased and pressure increased in patients with gynecological malignant tumor undergoing lithotomy position after operation, which are closely related to intraoperative pressure injury. Blood oxygen is a protective factor for intraoperative pressure injury, while pressure is a risk factor