The present invention relates to a thin film solar cell with light transmission. The thin film solar cell comprises a substrate, a front electrode layer, an absorption layer, a back electrode layer, a light-transmittance enhancing layer and an encapsulation layer, stacked in a sequence. Part of the back electrode layer is removed in depth so as to form a plurality of light-transmittance regions. Part of the light-transmittance enhancing layer and part of the encapsulation layer are disposed within each light-transmittance region. The light-transmittance enhancing layer has a refractive index between that of a first medium overlaid by the part of the light-transmittance enhancing layer disposed within each light-transmittance region and that of a second medium overlaying the part of the light-transmittance enhancing layer disposed within each light-transmittance region.