The invention relates to a detection device, specifically to a detection device for measuring beam center position of X-ray and y-ray used in a large-scaled container detection system. The detection device comprises a detector module, a detector pen holder, a fixed bracket, a rotary bracket, a shaft and a shaft sleeve, wherein, the shaft sleeve is fixed on the fixed bracket, the shaft is fixed on the rotary bracket, the rotary bracket is mated and closely connected with the shaft sleeve on the fixed bracket through the shaft, and the fixed bracket is fixed on the detector pen holder. The invention can accurately and rapidly measure the beam center position of the X-ray and the Y-ray, and has the advantages of simple structure, conveniently assembly and disassembly, easy operation, capability of operation at any time, and no limitations to time, place, weather and other factors.