BACKGROUND: Placenta mesenchymal stem cells have become hot spots in stem cells study in recent years because of its advantages. OBJECTIVE:To analyze the biological characteristics of amniotic mesenchymal stem cells and amnion epithelial cells, and to explore the feasibility of amniotic mesenchymal stem cells and amnion epithelial cells applied as seed cells in three-dimensional liquid culture to construct the tissue-engineered skin. METHODS:The amniotic mesenchymal stem cells and amnion epithelial cells were obtained by using multi-step digestion with trypsin and col agenase;then the flow cytometry, reverse transcription-PCR and immunofluorescent staining techniques were adopted to identify the surface molecular markers, stem cellcharacteristics and keratinocytes similarity respectively. Based on these data, amniotic mesenchymal stem cells and amnion epithelial cells used as seed cells together with rat type Ⅰ col agen matrix were adopted for three-dimensional liquid culture. RESULTS AND CONCLUSION:Flow cytometry test showed that amniotic mesenchymal stem cells and amnion epithelial cells cultured in vitro could highly express CD90, CD73 and CD105, and could not express the hemopoietic stem cellmarker of CD34 and MHC-class Ⅱ molecular HLA-DR. Reverse transcription-PCR results detected that amniotic mesenchymal stem cells could express stem cellcharacteristic genes CMCY and NANOG;amnion epithelial cells could express stem cellcharacteristic genes CMCY and KLF4, showing that both amniotic mesenchymal stem cells and amnion epithelial cells have stem cellproperties. Reverse transcription-PCR results showed that amniotic mesenchymal stem cells could express keratinocytes characteristic genes K19,β1-integrin and K8;amnion epithelial cells could express K19,β1-integrin, K5 and K8. Immunofluorescence staining results showed amnion epithelial cells could express keratinocytes proliferation related protein K14, which revealed that there was certain similarity in the mRNA expression between keratinocytes and amnion epithelial cells, and indicating that it has the potential to differentiate into keratinocytes. Tissue-engineered skin was successful y constructed by using amniotic mesenchymal stem cells and amnion epithelial cells, hematoxylin-eosin staining section showed that it has certain skin structure, and amnion epithelial cells had a preliminary differentiation. Al these prove that it is feasible to construct human skin tissues with amniotic mesenchymal stem cells and amniotic epithelial cells through the three-dimensional culture.