Background and objective: Priapism is an uncommon urological emergency, and is even less commonly caused by colon adenocarcinoma metastasis. The aim of this article is to report a case of malignant priapism caused by metastatic colon adenocarcinoma. Methods and materials: Case sharing and clinical experience summary of a 61-year-old man with priapism and hematuria persisting for more than 30 days presented to our hospital in September 2019. Results: The patient did not have a history of perineal trauma, nervous system disease, or hematological system disease. Penile Doppler ultrasound showed no obvious blood flow signal, and penile arterial blood gas parameters were pH of 7.01, partial pressure of oxygen of 26 mmHg, and partial pressure of carbon dioxide of 71 mmHg, suggesting the occurrence of ischemic priapism. Abdominopelvic computed tomography enhancement images showed a localized irregular shape and high-density imaging of the root of the corpus cavernosum. Histopathology after cystoscopy confirmed the metastasis of colon adenocarcinoma. Superselective embolization of the internal pudendal artery was performed, which partially relieve the abnormal penile erection, but drug treatment did not significantly alleviate the patient’s priapism. Conclusion: Priapism secondary to metastatic colon adenocarcinoma suggests systemic dissemination, indicative of a poor prognosis. In such cases, unnecessary surgery should be avoided. Superselective embolization could be an optional treatment for priapism secondary to cancer.