The invention provides an active cooling device and method for laser repairing of a single crystal turbine blade. The device comprises an air compressor, a heat exchanger and an annular cooling device. The air compressor compresses air to be cooled into high-speed and high-pressure airflow, and the airflow is introduced into the heat exchanger. After the introduced airflow is cooled by the heat exchanger, the airflow is introduced into the annular cooling device. The annular cooling device is arranged above a workbench of a laser cladding system and arranged around a workpiece. According to the active cooling device and method for laser repairing of the single crystal turbine blade, the volume and temperature of the cooled airflow and the position and angle of a cooling nozzle are adjusted, so that the best active cooling effect is achieved in the laser repairing process.