Rayleigh-Taylor instability is a typical benchmark in a computational fluid dynamics, which show interpenetrate materials happened when a heavy liquid is above a lighter liquid. In particle method, Shirakawa et. al. had been proposed a correction term on modelling a buoyancy force to show the phenomena of Rayleigh-Taylor instability (RTI) in the simulation. By adjust a specific value of correction term for a specific mass density ratio, Rayleigh-Taylor instability phenomena had been observed on MPS method. Later, the phenomena is also observed on FVP methods using the same modelling. In this study, several mass density ratio and viscosity ratio of liquids have been proposed as parametric simulation to observe Rayleigh-Taylor instability. The results show the correlations between mass density ratio and viscosity ratio in the specific correction term value of buoyancy model. This results confirmed that the RTI phenomena can be observed in specific mass density ratio.