Consumption of fossil fuel has led to serious environmental pollution, and an urgent demand for solar energy. Perovskite solar cell (PSC) is a device that converts solar energy into electricity. It is cost effective and power efficient, which has attracted much attention. However, PSC shows low absorptivity due to the limited thickness of the active layer. In this paper, a bilateral L-shaped metal grating structure is introduced into the PSC to enhance the absorptivity of the active layer by the surface plasmon effect between the metaling grating and the TiO2. With the deflection angle of the inner angle connection line of the metal grating is 45°, the inner angle distance is 100 nm, and the structural period is 250 nm, the absorptivity of the active layer of the PSC is 86.5% at 715 nm, which is 28.6% higher than the conventional solar cell at the same wavelength. Such results provide an effective way to improve the absorption of PSCs.