The patent technology of the long spiral mixing pile is one of the emerging construction technologies. It can be used in the foundation pile treatment, foundation pit supporting project and the waterproof curtain, especially in the construction in hard stratum. The combined support technology of long spiral mixing pile inserted steel pipe and composite soil nail was used in a sewage treatment project in Beijing, it not only met the requirement of supporting and waterproof, but also reduced the cost. The practice shows that the technology is safe, reliable, economical and useful.