Smooth blasting is of great significance to roadway stability and safety.The conventional smooth blasting method has some disadvantages when applied to the full-section blasting of a small section roadway in hard rock.Due to the selection of unreasonable charge quantity of the contour hole,hole spacing and decoupling coefficient,the phenomenon of backbreak or underbreak occurs after blasting.This approach can also lead to increased support work,decreased efficiency,and problems such as sidewall collapse and roof caving.To achieve a one-time full-section smooth blasting of the tunnel and reduce damage to the surrounding rock,an optimized smooth blasting method was developed.Six large-diameter empty holes with a diameter of 70 mm were designed at the periphery of the tunnel using the stress concentration effect of empty holes.The distance between the contour holes was reduced from 544~600 mm to 400 mm and evenly distributed around the tunnel contour.The contour holes were charged with the air decking structure and spaced at intervals of 0.4 m.The optimized smooth blasting method was applied in a test of a hard rock tunnel in the middle roadway of Heilangou Gold Mine at a depth of 500 m.Results show that compared with the traditional smooth blasting method,the optimized smooth blasting is more remarkable in technical,economic and safety aspects.The average footage increased by 0.03 m,the average half-hole rate increased by 34%,the explosive consumption decreased by 0.42 kg/m3,and the blasting operation cost decreased by 7.82 yuan/m3.The tunnel walls were smooth,and the roof stability was better,effectively reducing the disturbance to the surrounding rock,providing valuable experience for deep hard rock mining.