1. A method for optimizing flight speed of a remotely-sensed scan imaging platform, the method comprising: carrying the remotely-sensed scan imaging platform on at least one of an airborne vehicle and a satellite-borne vehicle, whereby the remotely-sensed scan imaging platform is positioned over a ground surface; selecting reference points on the ground surface by: selecting point A and point B on the ground surface as reference points, wherein a distance between point A and point B is L AB km; selecting the central point of a connecting line of point A and point B as a reference point C; and selecting point D as another reference point to make a connecting line CD of point D and point C perpendicular to the connecting line AB of point A and point B, and a distance between point D and point C be L CD km; obtaining, with an image sensor of the remotely-sensed scan imaging platform, a remotely-sensed scan image in a reference point region, and processing data; optimizing a flight speed of the remotely-sensed scan imaging platform.