The invention discloses a method and a device for adjusting a sensing threshold value of an infrared proximity sensor and belongs to the electronic technical field. The method includes the steps of obtaining a reflection infrared intensity value in a current light intensity environment through the infrared proximity sensor; comparing the obtained reflection infrared intensity value and a pre-saved reflection infrared intensity value and obtaining a first D-value; when the first D-value is larger than a first threshold value pre-saved, adjusting the sensing threshold value. In the invention, the reflection infrared intensity value is pre-saved in a cell phone and the reflection infrared intensity value in a current light intensity environment is obtained, then a judge about whether the infrared sensor makes a wrong judgment of shielding because the light transmittance lowers is made through comparing the obtained reflection infrared intensity value with the pre-saved reflection infrared intensity value, and the problem can be solved by adjusting the sensing threshold value without modifying hardware. Thus, the proximity sensing function of the cell phone can be repaired automatically.