Abstract: In this paper MoO₃/ITO（molybdenum oxide/tin-doped indium oxide）is proposed as the window layer deposited on the hole transport layer in semi-transparent bifacial perovskite solar cells. The molybdenum oxide（MoO₃）buffer layers with various thickness were prepared by evaporation. Given the PV Lighthouse simulation,the influence of MoO₃ buffer layer on the cell performance was systematically analyzed. Taking advantage of the wide bandgap of the electron transport layer and the anti-reflection effect of MoO₃/ITO layer stack,the short-circuit current density is improved as the cell illuminated from the glass substrate（SnO₂ electron transport layer）.It was shown that the fill factor and short-circuit current density reach the maximum when the thickness of MoO₃ buffer layer is in the range of 10-15 nm,leading to the highest conversion efficiency. Finally,a semi-transparent bifacial perovskite solar cells with a bifacial rate of 69.5% was obtained.