1. A method for setting a scanning protocol, comprising: creating a plain film positioning image; receiving a point of interest, a line of interest or a region of interest on the plain film positioning image input by an operator; generating a region to be matched, based on the point of interest, the line of interest or the region of interest; determining whether there is a pre-stored reference image having a matching degree greater than a preset threshold, by comparing pre-stored reference images with the region to be matched; obtaining a reference image in the case that a matching degree between the reference image and the region to be matched is greater than the preset threshold; selecting a scanning protocol corresponding to the reference image based on a preset correspondence between reference images and scanning protocols; and completing a setting of the scanning protocol in the case that there is the scanning protocol corresponding to the reference image.