Objective To study mechanical properties of the microstructure of the articular cartilage with biological activity by nanoindentation tests under the condition of keeping the articular cartilage in water. Methods The different abilities to keep in situ mechanical properties of the articular cartilage with cold mosaic method or with moisturizing method were evaluated by experiments, and the mechanical properties of the microstructure of the articular cartilage in different kinds of solution used in moisturizing method were also obtained. Results The experiment showed that the elastic modulus on the cartilage surface layer with cold mosaic method was much higher than that with moisturizing method, and the elastic modulus on the cartilage surface and deep layer in chitosan and saline were much lower than that in distilled water. Conclusions The moisturizing method is better at preserving in situ mechanical properties and biological activity of the biological materials, and chitosan and saline are proved to have the effect of keeping mechanical properties of the cartilage used in moisturizing method.