The invention belongs to the technical field of nuclear medical imaging and provides a breathing movement gating correction and attenuation correction method based on PET/CT imaging. The method comprises the following steps: obtaining phantom original data and CT image data of a detected object through PET/CT scanning; carrying out gating correction on the original data to obtain new gating data; reading in CT image data by analyzing and processing software, obtaining CT attenuation coefficient according to a CT image, converting the CT attenuation coefficient into an attenuation correction coefficient under PET energy, and solving an attenuation correction factor on each response line; importing the gating data into the analyzing and processing software and multiplying with the obtained attenuation correction factor, so as to obtain data after attenuation correction; and rebuilding the data after the gating correction and attenuation correction, so as to obtain a clear PET image. The method provided by the invention has the advantages that not only is the scanning time shortened, and also better image quality is obtained compared with an image only subjected to the gating correction.