To explore prognostic and predictive values of CT perfusion imaging (CTP) combined with Rapid automatic analysis software parameters in patients suffering from acute ischemic stroke (AIS) with anterior circulation proximal large vessel occlusion (ac-LVO) and undertaking endovascular therapy (EVT). Methods: A retrospective analysis of AIS patients with ac-LVO underwent EVT with or without intravenous thrombolytic therapy was performed. The data used for analysis were baseline characteristics and the CTP parameters post-processed by Rapid software, including the volume of cerebral blood flow<30% (VCBF<30% ), volumes of hypoperfusion with blood flow time to max>4 s, 6 s, 8 s, 10 s(VTmax>4 s, VTmax>6 s, VTmax>8 s, VTmax>10 s), hypoperfusion intensity ratio (HIR), mismatch volume (MMV), mismatch ratio (MMR), CBV index and Alberta stroke program early CT score (ASPECTS score). According to the modified Rankin scale (mRS), the data of 90-day follow-up was classified as good prognosis group with mRS of 0～2 and poor prognosis group with the mRS of 3～6. The differences in clinical data and CTP analysis parameters between the two groups were analyzed. Multivariate logistic regression was used to analyze the relevant independent predictors, the corresponding optimal thresholds of each predictor and their prediction capabilities by using the receiver operating characteristic (ROC) curve. Results: There were 158 patients enrolled, including 62 in the good prognosis group and 96 in the poor prognosis group. Multivariate Logistic regression analysis showed that VCBF<30% (OR=1.014, 95%CI 1.000～1.028, P=0.028), HIR (OR=8.655, 95%CI 1.800～41.620, P=0.007), systolic blood pressure (SBP) at admission (OR=1.039, 95%CI 1.015～1.064, P=0.001) and NIHSS at admission (OR=1.125, 95% CI 1.038～1.219, P=0.004) were independent predictors of prognosis. The analysis of ROC showed that the area under the ROC curve of HIR, VCBF<30%, systolic blood pressure at admission and NIHSS score at admission were 0.738, 0.704, 0.658 and 0.600, respectively, and that the best cut-off values for predicting adverse prognosis were HIR ≥0.355, VCBF＜30%≥25.5 mL, SBP ≥ 151.5 mmHg on admission, and NIHSS's score≥17 on admission. Conclusion: HIR, VCBF<30%, SBP at admission and NIHSS score at admission were independent factors influencing patients with ac-LVO during the follow-up for 90 days. HIR, and VCBF<30% showed advantages over NIHSS and SBP in predicting the prognosis for patients with ac-LVO.