Abstract: The experiment focused on obtaining the influenza virus in MDCK cell lines and Vero cell lines in the absence of trypsin by the way of continuous virus passage.First,the optimal pH conditions in which the virus can grow in the mammal cell lines was chosen.Then the virus separated and conserved by the lab were continuously cultivated in the Vero cell lines and MDCK cell lines in the absence of trypsin in the optimal conditions.After some passages,the original virus were mixed with the virus which have no Hemagglutinin titers,then these mixed virus and the virus which had the Hemagglutinin titers were cultivated in the cell lines.As a result there were six virus that can adapt to the condition in the absence of trypsin.