Abstract: Tho corrosion caused by Co₂ under proper humidity,a common problem in oil and gas gathering network, brings great harm to natural gas pipeline. The article deals with the forms of corrosion and the principle of Co₂ corrosion in this area.It also make fin analysis of the relationship between Co₂ dividing value and other faotors, presenting a formula showing the relationship between the corrosion rate and dividing. Finally it conludes that keeping oxygen off the gathering system, dewatering natural gas or urethane friction reducer can1 all prevent or inhibit corrosion effectively.