A method to simulate T2* shortening by the susceptibility of fat in the liver using FEM and simple modeling was developed. The model consisting of water and lipid droplets (LD) placed randomly. Simulation and in vivo studies indicated the feasibility of our method. The results suggested the microscopic field inhomogeneity by LDs leads to non-neglectable T2* decay. Besides, the result of in vivo study was fairly agreed with the simulation.