Abstract: The first problem to be solved in control engineering of debris flow included three relationships,namely,the relationship between the discharge of debris flow and cross section of the drainage channel,the impact force of debris flow and the strength of the dam,the material source graduation of the debris flow and the flexible protection.It is the key technology of debris flow controlling after the "8.8" extra large-scale debris flow in Zhouqu.It is proposed that long water with small drainage channel,general debris flow with middle drainage channel,large debris flow with large ecological landscape and leisure buffer.It solved the design requirements about flow and cross section of the drainage channel to the debris flow occurred once in hundred years.It is proposed that using reinforced concrete structure gravity dam replace the original gravity stone masonry wall.It meets the relationship of the impact force and strength of dam.Setting SNS flexible protection network in the circulation area is suggested.The use of wire rope ring network will bring into block and discharge.The research results have scientific value for the design to the post-disaster debris flow treatment scheme in Zhouqu.