Crystal structure of Li2BaSiO4 was reinvestigated by laboratory X-ray powder diffraction. The title compound was hexagonal with space group P63cm, Z=6, unit-cell dimensions a=0.810 408(2) nm, c=1.060 829(4) nm, and V=0.603 370(3) nm3. The initial structural model was successfully derived by the direct methods and further refined by the Rietveld method, with the anisotropic atomic displacement parameters being assigned for all atoms. The reliability indices calculated from the Rietveld refinement were Rwp=6.72%, S=1.17, Rp=5.06%, RB=1.86%, and RF=0.98%. The maximum-entropy method-based pattern fitting (MPF) method was used to confirm the validity of the structural model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The final reliability indices calculated from MPF were Rwp=6.74%, S=1.17, Rp=5.10%, RB=1.49%, and RF=0.69%. Atomic arrangements of the final structural model were in excellent agreement with the three-dimensional electron-density distributions determined by MPF.