Within density functional theory (DFT) calculations, we have studied the influence of different exchange and correlation functional on the site preference for CO adsorption on Co(0001) surface. All functional results identify atop and hollow sites as the favored sites with degenerate energy, also present almost identical adsorption geometries and vibrational frequencies for CO adsorption in each high symmetry site. However, based on empirical correction to adsorption energy, atop site is uniquely identified as the most favorable site, in perfect agreement with experimental results. This work provides another correct site preference with empirical correction to adsorption energy.