Abstract: Interface instability and turbulent mixing are complex multi-scale nonlinear physical problems, which have been found and utilized widely in man-made applications and natural phenomena such as inertial confinement fusion(ICF), high-speed combustion, and astrophysics (i.e. supernova explosions), so this problem has gained significant attention in science and technology. The Institute of Fluids Physics, China Academy of Engineering Physics has developed a large eddy simulation code MVFT (multi-viscous flow and turbulence)with different SGS models, based on Eulerian finite volune method. Meanwhile, the ability of different SGS models for simulating the interface instability and interface mixing has been evaluated in research. The effect of nonuniformity of flow field on the Richtmyer-Meshkov (R-M) instability was put forward, which has been successfully used to explain the related new experiment phenomenon and laws of the R-M instability. Given the found mechanism, the R-M instability and interface mixing in nonuniform flow were further studied and the effect of nonuniformity on the interface instability development in the strong nonlinear stage was discussed. Recently, the effects of initial perturbation on the R-M instability have been researched as well. Distinctive evolution mechanisms of R-M instability between the nonuniform flows and the uniform flows were analyzed in detail.