The invention relates to a detection device and a detection method of the weft breakage of a double-axis warp knitting machine. The detection device comprises a programmable computer controller, an input/output module and an irreflexive photoelectric sensor, wherein the programmable computer controller is connected with the input/output module through communication; and the irreflexive photoelectric sensor comprises an infrared transmitter module and an infrared receiver module which are connected with the input/output module through communication respectively. The detection method using the detection device comprises: setting the rotation period TR of the spindle of the double-axis warp knitting machine as D/RI; setting a yarn hanging mode M; detecting if a weft is broken according to the detected position of the weft by the programmable computer controller; and when the programmable computer controller determines the weft is broken, stopping the machine (including emergently stopping the machine) and stopping the weft breakage detection function. The detection device of the invention is simple in structure; and the effect of the detection of weft breakage by the detection methodis desirable.