The optical properties of polymer solar cells based on MoO3/Ag/MoO3 (MAM) transparent conductive electrode and ITO electrode were studied by transfer matrix method. The thickness of coupling layer, activation layer and metal electrode were optimized respectively, and the structure with excellent efficiency was obtained. The results show that MAM and ITO organic solar cells have obvious differences in optical properties under different active layer thickness and optical spacer thickness. The results show that the maximum short-circuit current density can reach 16.85mA/cm2 for thin active layer (100nm), which is 7.3mA/cm2 higher than that of ITO device. For thick active layer MAM electrode (270nm), the optical performance of ITO device is obviously better than that of MAM device. In addition, by changing the thickness of LIF, the critical thickness of optical spacer 30nm is obtained in our simulation.