In this condition, the nerve that governs the jaw movement is abnormally united with the upper eyelid, and no nerve impulse to the levator muscle occurs when the lid is closed, so the upper eyelid fissure is small or closed. In children, it is difficult to eliminate the abnormal jaw movement transient movement with levator muscle shortening. A frontal anastomosis with the levator aponeurosis flap can completely block the jaw movement transient symptoms. The mechanism of this procedure is to cut the levator muscle transversely at the superior border of the ligament of restraint and cut the ligament of restraint and levator muscle longitudinally on both sides of the incision to create a completely free trapezoidal levator flap, which causes the upper eyelid to be completely ptotic and causes the abnormal jaw movement to disappear. The levator aponeurosis flap is anastomosed to the frontalis muscle to correct ptosis using the power of the frontalis muscle. Therefore, a high level separation of the levator aponeurosis in the affected eye is a key step in eliminating the jaw movement transient symptoms. Another advantage of this procedure is that it maintains the integrity of the original structure of the levator aponeurosis at the lid plate attachment, so that the frontalis muscle is used to pull the levator aponeurosis to lift the lid, avoiding complications such as angular deformity of the lid margin and entropion that can occur with other procedures. This procedure is the first choice for mandibular transient syndrome. Therefore, the authors concluded that levator muscle dissection combined with levator flap frontalis anastomosis is the ideal procedure for the treatment of Marcus-Gunn syndrome.