Abstract: Objective To research the expressions of Snail and N-cadherin in osteosarcoma and to explore their roles in the carcinogenesis and progression of osteosarcoma. Methods Immunohistochemical assay(SP method) was used to detect the expressions of Snail and N-cadherin in 38 cases osteosarcoma tissues and 10 cases osteochondroma tissues. Results (1) Expression of Snail and N-cadherin in osteosarcoma was higher than that in osteochondroma,the comparative differences were significant(χ²=27.375，P<0.01,χ² =21.849，P<0.01).(2) Expression of Snail in osteosarcoma were concerned with soft tissue involvement,Ennecking stage,and lung metastases;and the comparative differences were significant (P<0.05). However,the expression of Snail in osteosarcoma were irrelevant with gender,age and mass site (P>0.05).The expression of N- cadherin was positively correlated with that of Snail(r=0.421，P<0.05).(3) The survival rate of the patients with positive express of Snail and N-cadherin was significant lower than those with negative express of snail and N-cadherin protein in osteosarcoma;and the comparative differences were significant(P<0.05). Conclusion The overexpression of Snail and N-cadherin in osteosarcoma means that they play synergetic roles in the process and metastases of osteosarcoma and poor prognosis.