Objective To obtain distributions of normal displacement on different layers of articular cartilage under sliding loads and investigate effects of compressive strain, sliding rate and sliding numbers on depth-dependent normal displacement of articular cartilage. Methods The non-contact digital image correlation (DIC) technique was applied to investigate the normal displacement of different layers for fresh pig articular cartilage under sliding loads, respectively. ResultsThe largest normal displacement was found on the superficial layer, while that on the deep layer was the smallest, with the middle layer was in between under sliding loads. The normal displacement for cartilage at different normalized depth increased with compressive strain increasing and the largest increasing amplitude was in the superficial layer. The depth-dependent normal displacement for cartilage decreased with sliding rates increasing. The normal displacement for cartilage kept increasing with different sliding numbers within its sliding time. The most significant increasing amplitude of normal displacement was found between the first and second slide. Conclusions Under sliding loads, the normal displacement of cartilage usually changes along with its depth from surface to deep layer, and compressive strain, sliding rate and sliding numbers all play important roles in such normal displacement distributions on different layers. These results can provide the basis for clinical cartilage disease treatment and cartilage defect repair, and are also important for structure and construction of artificial cartilage as well as in mechanical function evaluation.