Direct numerical simulation of Hz - O2 in the context of a temporally evolving mixing layer has been performed. Real molecular properties as well as the effects of the species differential diffusion were incorporated into an existing 3D parallel FORTRAN code. The geometry is a box with streamwise and spanwise directions being periodic whereas non-periodic boundaries were set up in transverse (vertical) directions which leads to inhomogeneity for the turbulent field in these directions. Initialisation were performed by error function distributions for streamwise velocity component, scalar mass fraction and temperature along the vertical axis of the domain, Initial pressure is set to be uniform and density Willi calculated based on ideal-gas law for the mixture. Disturbances were introduced by generating spanwise and streamwise vorticity in the middle of the mixing layer to enable transition from laminar to turbulent.