Abstract: To enhance the safety and reliability of tailing reservoir after closure and strengthen their safety management，take Aoshan General Tailings Reservoir as the engineering carrier.It constructs an intrin‐ sic safety enhancement technology system based on multi-factor synergistic optimization in response to the core problem of upgrading the flood prevention capacity after closure. Combined with the topographic charac‐ teristics of the reservoir area，“one side of the mountain，three sides of the dam”，under the premise of meet‐ ing the specifications and design requirements of the tailing reservoir，the comprehensive management meth‐ od of beach slope remediation and surface drainage ditch construction is adopted.The beach surface is graded according to a slope of 0.5% to 2%，sloping downhill toward the surface drainage ditch and drainage well ar‐ ea；four new drainage ditches are constructed on the beach surface，with the slope of the bottom of the ditch designed at a rate of 0.35% to 1.5%. After the implementation of the project，it has been verified that the con‐ struction of the beach drainage ditch can enable the rapid collection and discharge of rainwater，reduce the residence time of rainwater on the beach surface，prevent the retention of precipitation on the beach surface， and achieve the effect of reducing seepage and lowering the infiltration line of the dam body. The reservoir flood control capacity is 463 700 m3 ，an increase of 56% compared with the pre-rehabilitation period，which effectively improves the flood control capacity of the tailings reservoir；the maximum rise in flood level is 1.15 m，the maximum discharge flow rate is 24.32 m3 /s，and the calculated safe over-height is 3.05 m. The res‐ ervoir's flood discharge capacity has been upgraded from the upper limit of the third-grade reservoir（500 a） to the upper limit of the second-grade tailings reservoir（1 000 a）. The practice of this project confirms that the safety performance of the tailings reservoir has been further improved through the relevant technical transformation，which is conducive to the safety management of the tailings reservoir after its closure.

Key words: tailings reservoir, drainage system, flood control safety