When chewing food, the left jaw will make a rattling sound commonly seen in temporomandibular joint disorder, manifested as opening and closing the mouth popping, limited opening of the mouth or pain. When chewing food, the upper and lower teeth bite and the temporomandibular joints also move, but when the temporomandibular joint disorder, temporomandibular joints have functional or organic lesions, there can be joint popping when the upper and lower teeth bite, when the symptom is light, there is no obvious symptoms, and can be cured by wet and hot compresses or physical therapy, and the symptom is serious, there will be a limitation of opening the mouth, and the pain of pressing the joints is accompanied by the bone friction sound, and then we need to consider the hyaluronic acid injection or surgical treatment of the joint cavity. In this case, intra-articular hyaluronic acid injection or surgery should be considered. If the left jaw rattles when chewing, it is recommended to go to the dental hospital as soon as possible for examination and timely treatment.