For radical treatment of malignancies in the posterior region of the oral cavity and oropharynx, surgical exposure of the tumor by mandibulotomy is often required. Midline or paramedian vertical mandibulotomies are commonly performed in clinical practice, but these can damage the suprahyoid musculature and genioglossus, and weaken the swallowing and speech function of patients. Stair-stepped mandibulotomy is a new procedure, developed on the principles of functional surgery, that preserves the structure and function of the mandible whilst providing a clear field and avoiding damage to critical muscle attachments. Stair-stepped mandibulotomy is suitable for patients whose primary tumor is located in the middle and posterior part of the tongue or oropharynx, especially if the lesion involves extrinsic tongue muscles. In this case report, we draw on 2 cases of typical patients in our center to elaborate the surgery program design, operation points, advantages and disadvantages of stair-stepped mandibulotomy.