During tunneling, the slurry shield is often disturbed by many factors, i.e. limited environmental conditions, poor geological conditions, high soil and water pressure, complex and variable strata, etc. How to replace the disc cutter and gear cutter safely and efficiently has always been a problem for shield tunneling. To improve the safety and efficiency replacement of disc cutter and gear cutter of slurry shield, a method of replacing disc cutter and gear cutter under atmospheric pressure with high soil and water pressure is proposed. And then the working principle and main points of the technology are introduced; and the technology is applied to rivercrossing tunnel on Wuhan Metro Line No. 8. Finally, the detailed operation procedure and the superiorities of disc cutter and gear cutter replacement technology under atmospheric pressure are introduced according to characteristics of the uppersoft and lowerhard composite strata and project difficulties. By adopting the abovementioned technology, the cutter replacement efficiency has been improved, the construction safety risk has been reduced and the successful tunneling has been guaranteed.