Using well-practiced AFORS-HET software, thin film a-Si:H Bifacial Solar Cells (BFSCs) has been investigated and simulated. The aim of this study is to simulate performances of a-Si:H BFCs with structure of Glass/TCO/(n) a-Si:H/(i) a-Si:H/(p) a-Si:H/TCO/Glass. The results show that the optimized band gap for each layers are 2.0 eV (n-type), 1.7 eV (i-type) and 2.0 eV (p-type), respectively. The final simulation show that a significant increase VOC, JSC, FF and Eff for both side of a-Si:H BFSCs. Finally, the maximum efficiency obtained are 7.79% for the front side and 5.68% for the rear side, respectively.