A crystalline silicon solar cell capable of realizing double-side light entrance and a preparation method therefor are disclosed. The crystalline silicon solar cell comprises a metal grid line I, a transparent conductive oxide antireflection conductive layer, a doped silicon based thin film emitting electrode layer, an intrinsic silicon based thin film passivating layer, a crystal silicon wafer, a doped crystalline silicon thin film back surface field layer, a passivating antireflection layer and a metal grid line II. The preparation method comprises the steps of cleaning and texturing firstly, then preparing the doped crystalline silicon thin film back surface field layer, the passivating antireflection layer and the metal grid line II in sequence; then cleaning the surface, of the crystal silicon wafer, where the emitting electrode is positioned, then preparing the intrinsic silicon based thin film passivating layer, the doped silicon based thin film emitting electrode layer, the transparent conductive oxide antireflection conductive layer and the metal grid line I in sequence. The crystalline silicon solar cell has the advantages of capability of realizing double-side light entrance, high open-circuit voltage and good low light effect; the series resistance of the solar cell is further reduced, the consumption of valuable raw materials is reduced, and the cost is reduced; and in addition, the preparation method is suitable for large-scale production, capable of reducing the cost of the production equipment, and is expected to improve the stability and the yield of the products.