Abstract: Objective To study the differentiation on the immunogenicity of the leaflets, arterial wall and myocardium of conduit valved homograft(CVH) cryopreserved with liquid nitrogen . Methods Mono-cell suspension of leaflets cells and arterial cells of CVH were respectively co-cultured with human lymphatic cells whose blood groups were the same with that of CVH donors. Expressive levels of CD25 and HLA-DR of these lymphatic cells were detected by flow cytometry in the different cultural duration and compared with that of lymph cells alone cultured (comparative group). Results The immunogenicity of CVH artery walls was more severe than that of CVH leaflets, and expressive level of whose CD25 and HLA-DR was higher. The immunogenicity of CVH myocardium was not studied because the myocardial cell suspension were not be acquired in this study. Condusion It is proved that in vitro experimental study that the immunogenicity of arterial walls of cryopreserved CVH is more severe than that of leaflets