The invention relates to an on-line virtual testing system of a steel cord conveyor belt and a testing method thereof, and belongs the on-line testing technical field of coal mine equipments, the invention is characterized in that the system comprises a X ray source, a high frequency high pressure generator, a scan detection apparatus, an explosion-proof junction box, optical cables, a host computer, a base plate, a column and the like. According to the invention, a CMOS scan detector is taken as a testing method, novel ray detection elements can be arranged to an array, and an integrated circuit is directly connected with the array, the whole processes of ray reception, photoelectric conversion and digitalization can be synchronously completed, so that the CMOS scan detector has high acquisition efficiency and realizes the dynamic noise reduction, wherein the geometric size can reach at 0.08mm*0.08mm, thereby the characteristics of low noise, high sensitivity and high image resolution of the system dynamic detection can be guaranteed, and the problem that the imaging of steel cord is influenced by the vibration of the conveyer belt can be solved, the present invention has the advantages of compact structure and light weight, the normal demand of coal mine production can be satisfied, so that the on-line virtual testing system of steel cord conveyor belt and the testing methodare help for raising the safe production ability of coal mine.