The new g‐C3N4/activated carbon (AC) composites consisting of low‐cost and accessible materials, graphitic carbon nitride (g‐C3N4) and AC with different ratios, were designed and prepared for producing the Pd@g‐C3N4/AC (1:1) and Pd@g‐C3N4/AC (1:2) electrocatalysts. As‐prepared electrocatalysts were evaluated for the electrooxidation reaction of formic acid. Combining of g‐C3N4 and AC to form composites leads to improved catalytic performance of the electrocatalysts, especially for Pd@g‐C3N4/AC (1:1). The Pd@g‐C3N4/AC (1:1) electrocatalyst has a high electrochemically active surface area (ECSA) amount in comparison with the Pd@g‐C3N4/AC (1:2) electrocatalyst. Moreover, the current density of the Pd@g‐C3N4/AC (1:1) electrocatalyst is significantly larger than the other catalyst in the present .5 M formic acid. Therefore, the g‐C3N4/AC (1:1) composite has better physicochemical properties that can improve the catalytic performance of the related electrocatalyst.