A 35-year-old male patient was initially diagnosed with ciliary body melanoma due to blurred vision in the left eye, but postoperative pathology suggested adenoma of nonpigmented ciliary epithelium. He denied any family history, trauma or surgery history. He initially visited the ophthalmic outpatient department of Hunan Provincial People’s Hospital due to “blurred vision in the left eye for 6 years, significant decrease in visual acuity of the left eye with red eye swelling for 2 weeks. The orbital MRI showed an occupying lesion under the lens of the left eye, but its property was to be determined. The melanoma was diagnosed as “secondary glaucoma in the left eye, complicated cataract in the left eye, ciliary body mass with undetermined property in the left eye, binocular refractive error”. The intraocular pressure decreased after the treatment with drugs, but there was no significant improvement in the symptoms of visual blurring and ocular redness in the left eye. Then the patient was admitted to the Second Xiangya Hospital of Central South University. Both the speciality examination and the auxiliary examination indicated that the ciliary body of the left eye was occupied. Under general intravenous anesthesia, the left eye was treated with transscleral tumor resection, lens phacoemulsification, intraocular lens implantation and vitrectomy. Postoperative pathological examination showed that the tumor tissue was composed of a large number of proliferating columnar or cubic non-pigmented epithelial cells, and the tumor cells were arranged in cords, sheets or tubes. Immunohistochemistry showed CK18(+), s-100(+), Vim(+), GFA P(+), CEA(–), P63(–), ck5/6(–). The final diagnosis was adenoma of nonpigmented ciliary epithelium. It suggested that clinicians should pay attention to avoid missed diagnosis and misdiagnosis of ciliary body tumor.