This invention provides a scan method, scan system and radiation scan controller, and relates to the field of radiation. The scanning method includes obtaining detection data of an object to be inspected under radiation scanning using a detector, adjusting an accelerator output beam dose rate and/or an output electron beam energy level of a radiation emission device according to the detection data. With this method, working conditions of the accelerator of the radiation emission device may be adjusted according to the detection data detected by the detector, so that for a region having a larger mass thickness, a higher output beam dose rate or a higher electron beam output energy level is adopted to guarantee satisfied imaging technical indexes, for a region having a smaller mass thickness, a lower output beam dose rate or a lower electron beam output energy level is adopted to reduce the environmental dose level while guaranteeing satisfied imaging technical indexes.