Abstract　 　　 

　Matter mixing is one important topic in the study of core-collapse supernova (CCSN) explosion. In this talk, we perform two-dimensional hydrodynamic simulations to reproduce high velocity Ni56 clumps. Large density perturbation is proposed in the CCSN progenitor to generate Rayleigh-Taylor (RT) instability and make effective matter mixing. In the case of spherical explosion, RT instability is efficient at both C+O/He and He/H interfaces of the SN progenitor. Radial coherent structures shown in perturbation patterns are important for the obtaining of high velocity Ni56 clumps. We can also obtain mixing features and high velocity Ni56 clumps in some cases of aspherical explosion. These simulation results are roughly consistent with the observational findings of SN 1987A.