Abstract: According to the principal of Laryngotracheitis virus and Avian Pox virus all easy to multiplicate in epithelial cell, we have separately made the examination adapting the weak type L.T.virus and A.P.virus to chicken embryo skin cells and that causing cell pathological changes effort. After knowing well the law, we selected the third generation chicken embryo skin cell containing more L. T.virus and A. P. virus, causing cell pathological changes fast and mixed them according to the proportion 1:1. Then inoculated the mixed virus to chicken embryo skin cells and tested sparately the virulence of L. T. virus and A. P. virus multiplicatting in chicken embryo, in chicken embryo skin cell and the mixed virus using chicken embryo and cellls.The result is that the average virulence of L.T.virus and A.P.virus in C.E.S was respectively higher 0.7-1.0 titer than the same strain virus in chicken embryo. The average virulence of mixed virus was respectivel y lower 0.25-0.30 titer than that of the same strain in C. E. S, but higher 0.5-0.7 titer than that in chicken embryo. Because of this, L.T. virus and A. P. virus can multiplicate in the same cell at the same time. The result of this examination has opened up a new way for the research of diploid vaccine.

Key words: Avian virus, Cell Culture