AbstractIn pH 7.2 Na2HPO4‐NaH2PO4 buffer solution, polyphenoloxidase (PPO) could catalyze the oxidization of dopamine (DA) to form polymer particles in dark‐red color, which exhibited a strong resonance scattering (RS) peak at 780 nm. In the chosen conditions, as the PPO activity increased, the RS intensity at 780 nm increased linearly. The increased RS intensity (ΔI780 nm) was linear to the PPO activity in the range of 0.10–6.0 U·mL−1, with a regression equation of ΔI780 nm96.6C+15.1, a relative coefficient of 0.9987 and a detection limit of 0.06 U·mL−1 PPO. The proposed method was applied to detecting PPO activity in potato sample with satisfactory results.