Multiphysics of seismic analysis and reactive chemical transport analysis were conducted to evaluate the long-term environmental safety of hazardous waste landfills having a reinforced concrete structure. The structure stabilities when huge earthquakes occurred were assessed using seismic analysis. The bending moment generated in the reinforced concreate materials was converted into the crack width, and then the calculated crack width was applied as the boundary conditions of hazardous waste landfill for reactive chemical transport analysis. The results of reactive chemical transport analysis showed the long-term leaching concentration profiles from hazardous waste landfill and specified the factors affecting its environmental safety. This paper finally presents the importance of multi-barrier system consisting of stabilization/solidification techniques and artificial/natural soil sorption layer in order to minimize negative impacts of hazardous waste landfill.