Based on the scale of submerged spur-dike and flow-sediment condition in the first phase of the 12.5 m deep-water channel regulation project of Yangtze River downstream Nanjing, a normal model experiment is conducted to reveal the properties of maximum local scour depth around submerged spur-dike. The relationships of maximum local scour depth with the submergence ratio of submerged spur-dike, hydrodynamic condition and the width of bottom protective mattress are analyzed. An estimation formula of maximum local scour depth around submerged spur-dike is established through the experimental data by the principle of dimensional analysis. The formula yields well-fitting result. The study result can provide technical reference for the design of local scour protection in channel regulation.