If there is always a ringing sound in the left ear, it is recommended to go to an outpatient clinic and have an electronic tympanogram to improve the pure tone hearing threshold, and acoustic conductance resistance and other related tests. There may be the following diseases that can lead to these manifestations: 1. Cerumen embolism in the ear canal. The ear canal is blocked with cerumen, which is attached to the eardrum. When the patient opens the mouth, or when he or she is in an upright position, the cerumen rubs against the ear canal and the eardrum, resulting in the sensation of a ringing sound. In this case, the doctor can use a suction device or saline to flush out the cerumen, and once it comes out, most of this ringing sound will be gone. 2. Secretory otitis media and fluid in the tympanic chamber can easily induce vibration of the eardrum, and this ringing sensation can also occur. Other diseases, such as neurogenic tinnitus, abnormal opening of the eustachian tube, and arterial and venous objective tinnitus, etc., are also prone to the above-mentioned manifestations.