Objective: To study the application of CT and MRI fusion technique in the diagnosis and treatment of intraocular and orbital tumors. Methods: 2D-images of 13 patients with intraocular and orbital tumors were fused by special-point registration and Iterative Local Closest Point(ILCP) method; 3D-fusion images were reconstructed by Ray Tracing method. Results: A 3D-CT-MRI fusion images of intraocular and orbital tumors were reconstructed and displayed. The CT and MRI data of intraocular and orbital tumors were displayed on the same image as a comprehensive whole,which provided a stereogram of 3D-structure of the normal and abnormal orbital tissues. Anatomical structure of the orbit was clearly visualized by 3D-CT-MRI image. Conclusion: The multi-modality fusion technique can provide more accurate and comprehensive information for clinical diagnosis of intraocular and orbital tumors, which is helpful for doctors' planning of surgical operations,clinical education and doctor-patient communication.