The goal of this clinical trial is to evaluate the maintain effect of palatal surgery and oropharyngeal rehabilitation (OPR) by using the severity of obstructive sleep apnea (OSA), tongue muscle strength and the space of the upper airway in patients with OSA.The main questions it aims to answer are: 1. Will the severity of OSA, tongue muscle strength and the space of upper airway improve more in the palatal surgery combined OPR group than the other two groups? 2. Will The maintain effect of tongue muscle strength and the space of upper airway be better in the palatal surgery combined OPR group? Participants will be divided into 3 groups including palatal surgery combined OPR group, palatal surgery group and OPR group by the doctor's advice and their willingness.The OPR for the treatment groups included three 30-minute sessions of OPR per day, and the exercise would be performed 3-5 days per week for 3 months.