It is important to probe the effect of doping of ultratrace content of precious metal and synergistic effects of multimetals on effective electrocatalysts for water splitting. Thus, ultratrace content Ru doping NiMo-NC were acquired through simple hydrothermal technology and high-temperature pyrolysis. Benefiting from porous structure, ultratrace content Ru doping and synergistic effect of multiple metals, RuNiMo-NC-2 presents the small overpotentials of 130 and 199 mV for MOR to achieve 10 and 100mA cm−2 in 1 mol/L potassium hydroxide with 5 mol/L methanol. The assembled water electrolyzer with the RuNiMo-NC-2||RuNiMo-NC-2 couple only requires 1.49 V to realize 10mA cm−2 for the overall water splitting in 1 mol/L potassium hydroxide with 5 M methanol. This paper offers a feasible method for designing bifunctional electrocatalysts with superior electrocatalytic performance, which can be used in hydrogen production through water electrolysis.