Objective To retrospectively analyze the diagnostic modes, transsphenoidal microsurgical technique and outcomes of 145 patients with pituitary macroadenoma or giant pituitary adenoma.Methods A total of 145 patients suffering from pituitary macroadenoma or giant pituitary adenoma with suprasellar extension were performed with transsphenoidal microsurgery in our department. Diagnoses were made by CT or MRI scanning. All adenomas had suprasellar extension (extension size: >10 mm). Operations were performed via either sublabio-septo-sphenoidal approach or naso-vestibulo-sphenoidal approach under microscope. During operation, a subarachnoid catheter was inserted into the lumbar cistern, via the catheter saline was slowly injected to increase the intracranial pressure (ICP) and to deliver the suprasellar tumor into the operative field for easy removal.Results The gross total removal of adenoma in 102 patients (70.4%) and subtotal removal in 35 patients (24.1%) were achieved; partial removal was carried out in the remaining 8 patients (5.5%) with fibrous or dumbbell-shaped adenomas. There were no deaths after surgery. Long-term follow-up observation (median: 3.5 years) in 132 patients revealed good recovery in 93 (70.5%) and late recurrence in 39 (29.5%). Those patients with tumor recurrence underwent reoperation, drug therapy, radiotherapy, and radiosurgery either alone or in combination.Conclusion Except for fibrous and dumbbell-shaped ones, microsurgical technique via transsphenoidal approach is a safe and effective way to remove large pituitary adenomas.