Objective To analyze the changes in angiopoietin-2(Ang-2)levels before and after microwave ablation(MWA)in patients with high-risk pulmonary nodule and its impact on postoperative recurrence.Method A total of 94 patients with high-risk pulmonary nodules admitted to Guizhou Aerospace Hospital from December 2019 to December 2021 were included and categorized into a recurrence group(n=30)and a non-recurrence group(n=64).Clinical data was compared between the two groups.Pearson correlation analysis was used to analyze the correlation between pre-treatment angiopoietin-2(Ang-2)levels and CT parameters.Logistic regression model,restricted cubic splines,threshold effect analysis,and receiver operating characteristic(ROC)curve were used to analyze the relationship between pre-treatment Ang-2 levels and postoperative recurrence.Kaplan-Meier survival curves were used to analyze the differences in overall survival among patients with different Ang-2 levels.Cox regression model was used to analyze the factors affecting patients'survival.Result Compared to pre-treatment levels within the same group,Ang-2 levels in both groups decreased significantly,with statistically significant differences(P<0.05).Pearson correlation analysis showed that pre-treatment Ang-2 levels were positively correlated with BF,BV,PS,and MTT.Ang-2 level was independently associated with postoperative recurrence.Results of ROC analysis indicated that pre-treatment Ang-2 had certain predictive value for postoperative recurrence(area under the curve=0.789).Restricted cubic spline analysis revealed a nonlinear dose-response relationship between pre-treatment Ang-2 and postoperative recurrence(P<0.05).Threshold effect analysis identified that the inflection point of Ang-2 affecting recurrence as 1905.41 pg/mL.Survival analysis demonstrated that the median overall survival of patients in the Ang-2<1905.41 pg/mL group was longer than that in the Ang-2≥1905.41 pg/mL group(P=0.039).Furthermore,Ang-2≥1905.41 pg/mL was an independent factor affecting patients'survival time.Conclusion The levels of Ang-2 decreased significantly in patients with high-risk pulmonary nodules after MWA,and pre-treatment Ang-2 level has certain predictive value for postoperative recurrence.