Hydrogen economy has emerged as a promising alternative to the current hydrocarbon economy. It involves harvesting renewable energy to split water into hydrogen and oxygen and then further utilising clean hydrogen fuel for various applications. The rational exploration of advanced non-precious metal bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is critical for efficient water splitting. Herein, an ultralow Ru-modified cobalt metal-organic framework (CoRu0.06-MOF/NF) two-dimensional nanosheet array bifunctional catalyst was fabricated through a strategy under mild experimental conditions. The obtained CoRu0.06-MOF/NF exhibited excellent bifunctional electrocatalytic activity and stability in alkaline media, with low overpotentials of 37 and 181 mV and significant durability for more than 95 and 110 h toward the HER and OER at 10 mA cm-2, respectively. The experimental results showed that the two-dimensional nanoarray structure had a large specific surface area and abundant exposed active sites. Additionally, ultralow Ru modification optimized the electronic structure and improved the conductivity of the cobalt metal-organic frameworks, thereby reducing the energy barrier of the rate-limiting step and accelerating the water splitting reaction.