Engineering the interface between two-dimensional materials and polymers is of great importance to improve their catalytic performance for oxygen reduction reaction (ORR). Hence, polyaniline (PANI)-functionalized porous Pd metallene (Pd@PANI metallene) is prepared via a two-step strategy. Due to the ultrathin porous nanosheets and interfacial structure, the Pd@PANI metallene possesses sufficient active sites and optimized electronic structure, which exhibits superior oxygen reduction performance in alkaline electrolyte. The mass and specific activities for Pd@PANI metallene are measured to 1.79 A mgPd(-1) and 2.96 mA cm(-2) , which are 11.9 and 9.30 times those of Pt/C (0.15 A mgPd(-1) and 0.32 mA cm(-2)), respectively. Additionally, the ORR performance and morphology of Pd@PANI metallene can be maintained after long-term stability testing, making it an excellent ORR catalyst. This work provides an effective interface engineering strategy to construct efficient two-dimensional ORR electrocatalysts to improve the performance.