Monocrystalline silicon, a basic material for semiconductor devices, is characterized by high hardness, high brittleness, and low fracture toughness, which pose significant challenges to micro-nano processing. Laser machining is widely used to fabricate monocrystalline silicon microstructures, despite the accompanying notable thermal damage. To address this issue, a novel method is proposed for the through-groove machining of silicon wafers based on laser-electrochemical hybrid processing. This method leverages the photothermal coupling effect of lasers and increased conductivity of monocrystalline silicon with temperature, to achieve a combination of laser etching and electrochemical dissolution, thereby effectively improving the machining quality. The mechanism of laser-induced electrochemical machining is elucidated, and a corresponding experimental scheme is designed. Comparative experimental results demonstrated that laser-electrochemical hybrid processing surpasses traditional laser dry cutting methods in terms of surface quality. Further investigations into the effect of the applied voltage on machining surface quality revealed that at a voltage of 40 V, the surface roughness was significantly reduced to 310 nm, achieving optimal machining outcomes.