Painless lump in the floor of mouth should be treated according to the situation if it is cyst of sublingual gland; if it is cancer of the floor of mouth, it should be treated with surgery at an early stage. 1. Sublingual gland cyst: Sublingual gland cyst has no conscious symptoms in the early stage, with the gradual increase of the swelling, it may affect swallowing, speech and chewing. Therefore, small sublingual gland cysts are often left untreated; larger cysts are often resected, and the specific treatment needs to be treated according to the specific situation. 2. Cancer of the floor of the mouth: early stage of cancer of the floor of the mouth can be asymptomatic, but with the progress of the disease, there will be pain, obvious increase of saliva, insensitivity of tongue movement, difficulty in swallowing, etc. Generally speaking, surgical resection is often carried out in the early stage, and if there is distant metastasis of the tumor, palliative treatments, such as chemotherapy, radiotherapy, etc., are usually applied at this time. It can be seen that when painless lumps appear in the floor of the mouth, one should also pay attention to whether other symptoms appear, if so, one should consult a doctor in time to find out the cause of the disease, so as to achieve early diagnosis and early treatment.