Abstract: The conventional optical coherence tomography (COCT) can realize non-invasive and in vivo measurement with high spatial resolution and sensitivity. One of its applications is possible for obtaining birefringence information of biological tissues. In this paper, by use of a COCT system, articular cartilages with an animal model are studied. Layer structures formed on the COCT images are investigated in theory and experiments. The changes of layer structures of cartilage tissues on the COCT images with dehydration and mechanical action are analyzed, which shows that a COCT system may be capable of monitoring cartilage birefringence determined by the collagen fibre alignment and its packing density.