This study conducts an in-depth analysis of the Songze Site,a nationally protected cultural relics site,which is involved in the waterway improvement project of Youdungang in Shanghai.The research focuses on the optimization of waterway engineering schemes within the relics protection area and the corresponding impact evaluation on cultural relics.An optimal solution is proposed to maintain the original waterway width and form a rectangular channel cross-section through dredging.By applying theoretical calculations,numerical simulations,and a three-phase cultural relics impact assessment,the study establishes an integrated optimization model that incorporates technical design,navigation safety,and cultural relics preservation.The model systematically verifies the feasibility of the optimized engineering scheme.The results show that the cross-sectional coefficient of the optimized waterway decreases from 7.3 to 6.8,while the flow velocity increases from 0.24 m/s to 0.30 m/s,meeting navigation safety requirements.The optimized scheme applies static pressure construction technology to control dust and noise,while also complying with cultural relics protection standards.This research approach provides a technical pathway and evaluation method for engineering projects in similar cultural relics protection zones.