Leiomyosarcoma is a malignant neoplasm of smooth muscle origin and mostly originate from the wall of uterus and gastrointestinal tract, but primary leiomyosarcoma of the oral cavity is extremely rare. This tumor has a very poor prognosis due to high recurrence and metastasis rate, with 5 year survival rate of 32%. And regional lymph node metastasis is uncommon event. Complete wide surgical excision is the treatment of choice. A 64-year old man who had a painful ulcerative lesion on the labial & palatal gingiva of #11, 21 visited our department, and was diagnosed as leiomyosarcoma through a biopsy. Partial maxillectomy was carried out, with no following radiotherapy or chemotherapy. After months follow-up, there has been no evidence of recurrence or metastasis. But after months, we clinically find out two enlarged immobile palpable lymph node in right submandibular area of patient. So a biopsy was performed via an extraoral incision under local anesthesia. Histopathologic diagnosis diagnosis of the biopsy was lymph node metastasis of prior existed leiomyosarcoma. We report a case of a primary leiomyosarcoma occurred in a 64 year-old male patient involving the anterior maxillary region with regional lymph node metastasis with a review of literature.