Fuel Coolant Interaction (FCI), one of the critical phenomena in severe accident, involves a variety of physical phenomena including the interaction between coolant and fuel of high temperature. Especially, the jet break-up of a pre-mixing phase that the bulk of molten fuel breaks into the droplet is important for the accident progression. Understanding the intricate physics of jet break-up is essential to reduce the uncertainties of FCI and to mitigate severe accident. In this study, we have developed Lagrangian-based CFD code (named as SOPHIA) using Smoothed Particle Hydrodynamics (SPH) method, which has an advantage on handling the complicated interfacial behaviors, large deformation and multiphase flow. Furthermore, the SOPHIA code is parallelized on the multi-GPUs to achieve high-resolution and large-scale simulation that enhance the accuracy and practical applicability. Using the multi-GPU based SOPHIA code, this study simulates the benchmark jet breakup experiments in high resolution and three dimensions. The simulation results are compared with the experimental data both qualitatively and quantitatively. As a results, they shows a good agreement, and furthermore, three dimensional high resolution simulation is confirmed to resolve the physical features of jet breakup accurately by taking account into the multi-fluids interactions between jet-pool-air.