Black watery vaginal discharge is mainly a symptom caused by vaginal melanoma, a black watery vaginal discharge health search, also known as black belt. In combination with infection, there may be a bloody, foul-smelling, purulent discharge. The cause of black watery vaginal discharge is due to the development of melanoma in the vagina. Vaginal melanoma has a typical clinical presentation. The clinical diagnosis is easier to obtain when a vaginal lesion is found on gynecologic examination, and pathologic examination can be performed by punching a biopsy or removing the entire lesion in suspicious cases. The cut edge includes 1 to 2 cm of normal vaginal mucosa to prevent spread of the tumor during biopsy, and the excised tissue is confirmed by rapid freezing to expand the scope of the procedure according to the situation. Non-epithelial malignant tumor cells are seen on smears. Vaginal melanoma should be differentiated from other rare melanoma-containing tumors such as pigmented neurofibroma and malignant nerve sheath tumors. The cell types of vaginal melanoma are diverse, and in particular, anaplastic vaginal melanoma is easily misdiagnosed with vaginal squamous carcinoma, vaginal adenocarcinoma, and sarcoma, with a misdiagnosis rate of 20%. It is mainly distinguished from other diseases by immunohistochemical staining and electron microscopy, which is more accurate than HMB-45 staining. It should also be thought to differentiate from the rare vaginal mucosal nevus nigricans and to exclude metastases from other sites and invasion of malignant melanoma from adjacent organs; changes at the mucosal junction are the most reliable basis to prove primary.