Developing readily-available, highly-efficient and stable electrocatalysts for water splitting is a challenge. Herein, a novel non-precious metal catalyst via coupling the N-doped carbon dots (NCDs) with the W doped CoP that is assembled on Ni foam (W_y-CoP@NCDs_x/NF) has been developed as the efficient bifunctional catalysts for overall water splitting. Specifically, the optimal W_0.03-CoP@NCDs_0.5/NF catalyst exhibits typical urchin shape under the regulation of the NCDs, showing abundant active sites. Meanwhile, the W-doping modulates the electronic structure and lowers the energy barrier of the catalyst. Moreover, the porous Ni foam as the catalyst supporter enables to expose catalyst more active sites and accelerate electron transfer. Beneficially, the optimal W_0.03-CoP@NCDs_0.5/NF only requires 136 mV and 305 mV overpotentials in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to reach the current density of 100 mA·cm⁻² in 1.0 M KOH, respectively. More importantly, the electrolyzer assembled by such W_0.03-CoP@NCDs_0.5/NF consumes a cell potential as low as 1.664 V to afford a large current density of 100 mA·cm⁻² with remarkable stability, which offers great promise for practical applications.