Herein, well-dispersed porous AuPt alloy nanodendrites (AuPt NDs) were facilely synthesized by a single-step seedless approach by using 5-aminouracil-6-carboxylic acid (AUCA) as the capping agent and weak stabilizer. The architectures showed large electrochemically active surface area (29.67 m2 g−1), and enhanced catalytic performances for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) both in acid and alkaline media. Specifically, the mass activity and specific activity of the as-made catalyst were 31.55 mA mg−1 and 2.65 mA cm−2 (0.1 M HClO4), 29.49 mA mg−1 and 2.5 mA cm−2 (0.1 M KOH) for ORR, respectively, along with a notably low Tafel slope of 34 mV dec−1 (0.5 M H2SO4) and 55 mV dec−1 (0.1 M KOH) towards HER. This synthetic approach can be explored to fabricate other catalysts with improved catalytic performances in fuel cells and renewable energy.