【Abstract】 Objective To explore the weaning success rate of patients with mechanical ventilation in intensive care unit (ICU) under lowlevel PSV and T tube test and compare the value of two comprehensive weaning parameters (CORE index, RSBI value) in predicting the weaning success. Methods The clinical data of 106 patients with mechanical ventilation admitted to the ICU of First Hospital of Qinhuangdao from January 2019 to December 2019 were retrospectively analyzed. The patients were divided into lowlevel pressure support ventilation group (PSV group, 49 cases) and T tube test method (T tube group, 57 cases) according to the weaning SBT modes. The weaning parameters of all patients were recorded before SBT. The CORE index and RSBI value were calculated. The general data, weaning parameters and weaning success rate were compared between PSV group and T tube group. The differences in CORE index and RSBI value of patients with weaning success and patients with weaning failure were analyzed in PSV group and T tube group. The receiver operating characteristic curve (ROC curve) was drawn to analyze the predictive value of CORE index and RSBI value on weaning success in the two groups. Results There was no statistical difference in the weaning success rate between PSV group and T tube group (69.39% vs 64.91%) (P＞0.05). There were no significant differences in the gender, age, APACHEII score, mechanical ventilation time, VT, f, PaO2, PaCO2,PImaxand RSBI value between PSV group and T tube group (P＞0.05), but P0.1 in PSV group was low than those in T tube group, and the CORE index was greater than that in T tube group (P＜0.05). Among 106 patients, the CORE index in weaning success group was significantly greater than that in weaning failure group (P＜0.05) while the RSBI value was significantly smaller than that in weaning failure group (P＜0.05). The areas under the ROC curves of overall CORE index and RSBI value were 0.882 and 0.742 in predicting weaning success. The CORE index of patients with weaning success in the two groups was greater than that of patients with weaning failure (P＜0.05) while the RSBI value was smaller than that of patients with weaning failure (P＜0.05). The areas under the ROC curves of CORE index and RSBI value in predicting weaning success were 0.966 and 0.792 in PSV group and were 0.805 and 0.686 in T tube group respectively. Conclusion Lowlevel PSV method or T tube test method for ICU patients has no significant effect on weaning success rate. Both CORE index and RSBI value have a certain predictive value on weaning success, and CORE index has a higher predictive value and shows higher predictive value when PSV method is used for weaning.