Objective: To analyze the value of multi-phase vascular fusion based on computed tomography angiography (CTA) in qualitative diagnosis of pulmonary space-occupying lesions. Methods: A retrospective analysis was performed on the data of 185 patients with pulmonary space-occupying lesions who had pathological results. All patients received conventional contrast-enhanced chest CT followed by chest CTA. Using pathological results as the reference standard, the diagnostic efficacy of the two examination methods was assessed. Results: The sensitivity and specificity of conventional multi-phase contrast-enhanced CT were 87.50% and 84.62% (Kappa value=0.709), and the area under the curve (AUC) was 0.861. The sensitivity and specificity of multi-phase vascular fusion based on CTA were 95.83% and 93.85% (Kappa value=0.893), and the AUC was 0.948. Delong’s test showed that the AUC of multi-phase vascular fusion was greater than that of conventional multi-phase contrast-enhanced CT (P<0.05). Conclusion: Multi-phase vascular fusion based on pulmonary CTA can better display blood supply characteristics of lesions and improve the diagnostic efficacy for benign and malignant lesions.