Theoretical calculations reveal that aluminum (Al) doping can effectively modulate the electronic structures of 2D ruthenium (Ru) catalysts. Moderate Al incorporation can endow Ru nanosheets with more delocalized electrons and optimal hydrogen adsorption Gibbs free energy, providing opportunities to achieve improved hydrogen evolution performance. Thus, Al-doped Ru nanosheets have been synthesized by a solvothermal strategy, in which they exhibit holey nanosheet structures and have more active sites exposed on the basal plane. The characterizations unraveling the Ru structure can be well maintained, and electrochemical measurements confirm the appropriate amount of Al modulation that can extremely enhance its hydrogen evolution activity.