In this paper, we are investigating theoretically the behavior of a bifacial silicon solar cell in steady state with different illumination conditions. The bifaciality coefficient and the conversion efficiencyare calculated for various rear side illumination conditions (traduced here by the illumination level) and back surface recombination velocity, taking into account the base doping density. The main purpose of the work is to show that bifacial illuminationcan improve significantly the conversion efficiency of the solar cell and to exhibit the role of the back surface recombination velocity, the base doping density and the rear side illumination conditions in the performance of the bifacial silicon solar cell.