Film cooling holes are important cooling structures on aero-engine turbine blades. Lasers can fabricate high-precision film cooling holes on complex turbine surfaces. The recast layer produced during laser machining will reduce the cooling effect. Although ultrafast lasers are usually regarded as “ cold ” processing, thermal damage can also occur in high-power and high-repetition rate ultrafast lasers. The focus of laser processing film cooling hole technology is multifaceted, and the formation mechanism of the recast layer and its inhibition method are key points of laser processing film cooling hole technology. At present, research on laser processing of the recast layer of film cooling holes focuses on the influence of parameters. Some achievements have been made in the research of laser processing of the recast layer of film cooling holes, but the formation mechanism of the recast layer has not yet been solved. It is possible to characterize and analyse the recast layer from its metallographic structure and element composition. This paper introduces the processing principle and status of laser processing of film cooling holes. Then, it summarizes the relevant research on the recast layer of microholes and finally the current theoretical research on the formation mechanism of the recast layer.