The invention relates to the field of quarantine irradiation treatment for agriculture and forestry products and provides a method of X-ray irradiation treatment for log quarantine and a device thereof. The method includes the following steps: log carrying vehicles are connected with a pulling device automatically, and a protective door is opened; the log carrying vehicles are dragged into a quarantine irradiation channel, and the protective door is closed; when the log carrying vehicles get to an irradiation field, accelerators emit beams and the log carrying vehicles are dragged through theirradiation field by the pulling device so as to achieve the quarantine irradiation of the complete vehicle of logs, then the accelerators are closed; after the quarantine irradiation is finished, theprotective door is opened, and the log carrying vehicles are dragged out of the quarantine irradiation channel; the pulling device and the log carrying vehicles are disconnected. The device comprisesthe accelerators, a shielding structure, the pulling device, rails and channels, wherein the accelerators are distributed on two sides and at the top of the channels in an axial symmetry manner. Themethod has no limit on the environmental temperature of the irradiation treatment or environment pollution, and has high treatment speed, safety and reliability.