Objective: To study the method and long-term curative effect of diode laser interstitial heat therapy for pituitary tumor by transnasal-sphenoidal approach conducted by CT or X ray. Methods: 805nm diode laser, output power of which is 25W, optical fiber is conducted by transnasal-sphenoidal approach through CT or X ray to have heat therapy. Results: Symptoms get better for all 3 patients, and endocrine indexs are normal. 1 patient has no pituitary tumor 1 year after operation, and 1 patient is made craniotomy 2 years after operation. Conclusion: This methods have advantage of simple manipulation, accurate location, slight injury, less complication, less painful and economics.