Placental site trophoblastic tumor (PSTT) is a rare type of gestational trophoblastic neoplasia (GTN). It is rising from the abnormal proliferation of intermediate trophoblastic cells with occasional multinuclear giant cells, with the potential for local invasion and metastasis. For its untypical and changeable clinical characteristics, the diagnosis and management are still poorly understood. Here we documented a case of PSTT with vaginal lesion as her unique presentation. After surgery and adjuvant chemotherapy, the patient was cured.