Objective　To explore microsurgical anatomy and clinical effects of the improved extended transbasal approach with preservation of olfaction.　Methods　The anatomic features were observed and measured in 20 dry skulls and 15 wet cadaveric heads. From March 2005 to June 2010, thirteen patients with tumors in midline of skull base were surgically treated through the extended transbasal approach with the preservation of olfaction function.　Results　The extended transbasal approach provided a significant increased operating field compared to that of the standard transbasal approach. Nasal mucosa attached to the cribriform plate could be remained by removing the nasal bone and orbital plate during the osteotomy. The optic nerves，carotid arteries，vidian canals，hypoglossal canals and other structures would be the perturbation for the further extension of operating field. 9 among 13 patients were totally removed the tumors. Five patients occurred postoperative complications. No surgical mortality occurred.　Conclusions　The main apparent advantages of the improved approach are the quality of surgical exposure, a low risk of brain damage, and the effective preservation of olfaction, which is an optimal selection for resecting the tumors in the midline part of skull base involving the orbit, paranasal sinus, ethmoid sinus, sphenoid sinus and clivus regions.