The utility model relates to a super-large container weld joint flaw detection device which is provided with a long-strip support, double-row chains are installed at the upper end and the lower end ofthe long-strip support through chain wheels, and the chain wheel located on the upper portion is driven by a chain lifting motor to operate. Linear sliding rails are arranged on the portions, locatedon the two sides of the double-row chain, of the long-strip support in the vertical direction, an installation base plate is further fixedly connected to the double-row chain, a directional X-ray flaw detector is installed on the installation base plate, and a plurality of sets of supporting idler wheels rolling along the inner wall of the large container are further arranged on the side, close to the wall of the container, of the long-strip support. An installation clamping base is further arranged at the top end of the long-strip-shaped support, one end of the installation clamping base isfixedly connected to the long-strip-shaped support, a weight box is installed at the other end of the installation clamping base, a network assembly is installed in the weight box, an annular walkingwheel is installed in the middle of the installation clamping base, and an annular walking driving motor is further installed on the installation clamping base. The device is compact and practical instructural design, automatic, flexible and convenient to operate and good in use effect, and has good actual use and popularization value.