A mechanism of quantitative dual-spectrum IR imaging (QDS-IR) system for examining the breast cancer is reported. The major mechanism of the system is a pair of long-wave Infra-red (LIR) and middle-wave Infra-red (MIR) cameras with the keen temperature sensitivity and the high spatial resolution. The optical axes of cameras are calibrated by the help of two calibration makers set up on the seat for carrying an object to make them parallel to each other and locate on the same level. The design provides an imaging system with the high reproducibility supported by 7 free degrees and the high adjustability. The proposed system could ensure the positions of the object and two cameras are the same at the different time points and find the best relative positions between the seat and two cameras for the objects with different body types. Therefore, it has potential ability to detect breast cancer or monitor the effect of chemotherapy.