The utility model relates to an adjusting device and welding seam detecting system, adjusting device includes: X includes adjusting device and sets up the welding seam check out test set on the carrier seat that holds at adjusting device to adjustment subassembly, welding seam detection device to adjustment subassembly and Z to adjustment subassembly, Y, the welding seam check out test set is theX X -ray radiographic inspection machine, and the side at the jar body is fixed to adjusting device's slide rail, and the slide rail arranges along jar length direction of the body that slide rail length is not less than jar length of the body, through many circumferential welds and many longitudinal seams of the X X -ray radiographic inspection machine detection tank body. This adjusting device,the manual diversified range adjustment that carries out the defectoscope of welding seam detecting system ability, it is easy and simple to handle, showing reduction working strength, reinforcing welding seam detection efficiency.