Addressing the high‑energy‑consumption issue caused by turbulence in fluid pipeline transportation，this study introduces polyacrylamide drag‑reducing agents into the flow field.By combining numerical simulation and particle image velocimetry （PIV） experiments，the influence of the drag‑reducing agent on the turbulent drag reduction characteristics in a circular pipe is investigated，and the intrinsic relationship between the drag reduction performance and the flow field structure is revealed.After comparing three low‑Reynolds‑number k-ε models，the Lam-Bremhorst model was selected for its simulation accuracy above 96.56%.Results indicate that DRA addition thins the near‑wall boundary layer，enhancing flow performance and suppressing turbulence.In the flow rate range of 5.7~13.7 m³/h，drag reduction reaches 30%~40.9%，centerline flow velocity increased by 2.97%~2.24%，turbulence intensity decreases by 3.86%~3.81%，and near‑wall turbulent dissipation drops by 45.2%~28.6%.Mechanistic analysis shows that polyacrylamide molecules generate elastic stress in the near‑wall region.This both suppresses turbulent coherent structures and kinetic energy fluctuations，and thins the boundary layer while improving the velocity profile，thereby reducing flow resistance.The study provides a theoretical basis for understanding the near‑wall action mechanism of DRAs and for improving energy efficiency in pipeline flow.