Medulloepithelioma of the ciliary body is a kind of malignant tumor which arises from neuroepithelium. It is easily misdiagnosed or miss diagnosed due to its masquerade feature in the clinical practice. We report a boy with a tumor in his right eye at age of 3 years and 9 months presented first with lens rupture. Diagnosis of malignant medulloepithelioma of ciliary body was made pathologically by biopsy of the partial tumor.