An apparatus and a method for controlling oil of a multi-compressor installed in an air conditioner includes a microcomputer for sequentially stopping compressors installed in the air conditioner for a preset time and then sequentially operating the compressors when the preset time elapses; and oil pipes connected to the compressors and balancing oil in the compressors, so that damage of the compressors due to imbalance of refrigerating machine oil is prevented by uniformly dividing oil of a multi-compressor installed in the air conditioner.