Abstract: A method for detecting a blockage in a filter mesh of an indoor unit includes: obtaining a first resistance difference value of the filter mesh under a preset air volume value; determining a first external static pressure value during an operation process of the indoor unit; and determining that the filter mesh is blocked based on a numerical relationship between the first external static pressure value, the preset external static pressure value, and the first resistance difference value. The blockage of the filter mesh may be determined in time during the operation process of the air conditioner.