We report one algorithm for simulating oxygen K-edge RIXS for weakly correlated systems, using maximally localized Wannier functions as the basis set. The N-electron wavefunction is formulated using the single Slater determinant, and the many-body effect is treated explicitly at the dipole matrix element level. The simulated result of oxygen K-edge RIXS for solid state Li2CO3 matches well with the experimental data. Besides being efficient and reasonably accurate, this algorithm also shows potential to extent to more complex RIXS problems.