The present invention relates to a method for repairing an abradable coating of a compressor of a gas turbine, where a worn abradable coating is repaired, where an analysis and/or selection of areas of the abradable coating to be repaired is conducted by means of a boroscope in the non-removed state of the gas turbine, where a tool is passed through at least one boroscope aperture of the gas turbine to the area to be repaired and the worn abradable coating is at least partially removed, where the removed material is extracted, where the area of the abradable coating to be repaired is cleaned and/or prepared for application of a repair medium, where a hardenable aluminum oxide-based repair medium is applied to the area to be repaired by means of a type of airbrush and then hardened, and where the area provided with the repair medium is subsequently mechanically treated.