Bilateral maxillary sinus can be seen in the increased density shadow may be maxillary sinus purulent secretion, maxillary sinus mucosal thickening and maxillary sinus tumor and other conditions. 1. Purulent secretion in the maxillary sinus: increased purulent secretion in the maxillary sinus is common in acute sinusitis, stimulating hypersecretion of sinus glands or bacterial infections, resulting in increased secretion, the patient can be manifested as a bilateral nasal discharge of yellow nasal mucus, persistent nasal congestion, headache and other symptoms. 2. Mucosal thickening of maxillary sinus: the mucosal edema or hyperplasia in the sinus can be caused by acute and chronic inflammatory reaction, which is shown as relative high density shadow on imaging. Patients may be asymptomatic or have discomfort such as facial distension and pain. 3. Tumor of maxillary sinus: the tumor shows high-density shadow in imaging, and patients have repeated bloody nasal discharge, swelling and deformation of the face. Some patients may have facial pain or abscess fistula formation. The appearance of maxillary sinus high-density shadow, need to go to the hospital, after the systematic examination of a clear diagnosis.