Objective To explore the value of multimodal image fusion technique in neuroendoscopic endonasal treatment of anterior skull base tumors. Methods The clinical data of 9 patients with anterior skull base tumors who underwent endoscopic surgery at Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University from January 2016 to June 2017 were retrospectively analyzed. CT, MRI, and CT angiography (CTA) images of the patient′s skull were fused before surgery, and intraoperative neuronavigation assisted surgical removal of the tumor was performed based on the results of the image fusion. This paper analyzed the effects of multimodal image fusion technology on demonstration of anterior skull base lesions and adjacent anatomical structures. Results During operation, multimodal image fusion clearly revealed the anterior skull base tumors together with adjacent neural tissues, blood vessels, bone structures, sphenoid sinus and septations. All 9 patients underwent successful operation. Among them, gross total resection of tumor was achieved in 6 cases and subtotal resection in 3 cases. No serious complications such as delayed hemorrhage, brain infection, and cerebrospinal fluid rhinorrhea occurred postoperatively. Conclusions In neuroendoscopic transnasal resection of the anterior skull base tumor, the application of multimodal image fusion technology combined with intraoperative neuronavigation can clearly show the location of tumor and its adjacent important structures, which helps improve the accuracy, safety, and effectiveness of the operation. Key words: Skull base neoplasms; Neurosurgical procedures; Neuronavigation; Natural orifice endoscopic surgery; Multimodal