Abstract: Marek’s Disease Virus (MDV) Chinese strain GX0101 was the first reported recombinant MDV field strain with one Reticuloendotheliosis Virus (REV) Long Terminal Repeat (LTR) insert. REV LTR in the GX0101 genome increased the potential for horizontal transmission. REV LTR fragment has the biggest impact on SORF2 gene. Researchers detected the influence of SORF2 gene deletion on its horizontal transmission ability by real time PCR. The result shows that GX0101ΔSorf2 possesses similar replication ability with bac-GX0101 no mater on the level of lymphocyte or feather follicle. Although, researchers can detect MDV positive in feather follicles of sentinel in contact chickens at age 10 in both groups respectively, the number of SPF chickens infected with bac-GX0101 by contact is higher than the number of GX0101ΔSorf2 infection group. Therefore, SORF2 gene has certain effect on the horizontal transmission ability of the virus.