Background: Giant pituitary adenomas continue to carry higher surgical risks, and postoperative acute catastrophic hemodynamic changes are associated with very poor outcome but remain difficult to predict. Method: Surgical planning based on information about the fine angioarchitecture was achieved using C-arm cone-beam computed tomography. Particular feeding systems and semi-quantitative evaluations for tumor staining were also investigated. Conclusion: Major blood supply was different from the normal supply to the anterior pituitary gland and did not necessarily correspond to tumor shape and extension. Surgical strategy should be established based on the tumor feeding systems and hemodynamics in giant pituitary adenomas.