A X-ray device and an image-acquiring method thereof are provided. The X-ray device includes a C-arm X-ray equipment and an image-positioning device. The image-positioning device is disposed on a X-ray receiving part of the C-arm X-ray equipment. The image-positioning device includes a positioning plate and a positioning ring. The positioning plate includes a plate substrate and a plurality of first ball objects. The first ball objects are disposed in the plate substrate and arranged asymmetrically. In the image-acquiring method, at first, the X-ray device is provided. Then, a X-ray image is acquired by using the X-ray device. Thereafter, plural first auxiliary marks are used to calibrate the X-ray image, in which the first auxiliary marks correspond to the first ball objects.本發明提供一種X光裝置與其影像擷取方法。此X光裝置包含C型臂X光機以及影像定位裝置。此影像定位裝置係設置於C型臂X光機之X光接收部上。影像定位裝置包含定位盤和定位環。定位盤包含盤狀基材與複數個第一球狀物。第一球狀物係設置於盤狀基材中，且彼此不對稱排列。定位環包含環狀基材與複數個第二球狀物。第二球狀物係設置於環狀基材中且彼此不對稱排列。在前述之影像擷取方法中，首先提供前述之X光裝置。然後，利用X光機來擷取X光影像。接著，利用X光影像中的第一輔助標記來扭正X光影像，其中第一輔助標記對應至第一球狀物。
