Abstract: Provided are a metformin inhalation powder aerosol for treating idiopathic pulmonary fibrosis and a preparation method thereof, including following steps: pretreating a metformin raw material to obtain fine powder, and passing the obtained fine powder through a screen with a mesh size of 100-1000 microns by an pendular granulator at a rotating speed of 200 revolutions per minute to obtain soft particle clusters; pre-spheronizing clusters at a vibration frequency of 100-300 hertz to obtain particle clusters, and then rolling the particle clusters on a granulating pan and spheronizing to obtain spherical particle clusters.