In this work, a one-step electrodeposition so-called "dynamic hydrogen bubble template" (DHBT) method was proposed to fabricate a porous Au film electrode. Field emission scanning electron microscopy and cyclic voltammetry techniques were used to characterize the as-prepared film, and results confirmed the formation of honeycomb-like dendritic (HCLD) porous structures with enhanced surface area and roughness factor. The resulting HCLD-porous Au film electrode was explored for enzyme-free H2O2 reduction and a remarkable electrocatalytic activity was observed in terms of reducing the overpotential similar to 0.5 V towards more positive potential with similar to 3-fold enhancement in current signal in comparison to the bare Au electrode. The fabricated sensor displayed excellent analytical response in amperometric mode at an applied potential of -0.1 V in a linear range from 0.02-0.36 mmol L-1 with a detection limit of 0.003 mmol L-1 and a sensitivity of 1176 mu A mmol L-1 cm(-2). Besides, the sensor exhibited good selectivity and reproducibility. Lastly, the proposed sensor was evaluated for real application using mouthwash liquid samples via standard addition method and the recovery value was found to be similar to 97%.