Friction factor estimation is a key component of pipeline system design. Introduced in detail is the new GERG friction factor equation proposed by GERG Company, conducted is contrastive analysis on GERG equation, Weymouth equation, Zegarola equation and classical Colebrook-White equation and these equations are applied to actual pipeline operation data calculation and such conclusions can be given that Weymouth equation can be applied to friction factor calculation of pipeline with k from 20μm to 30μm wall roughness, Zegarola equation can be applied to friction factor calculation of pipeline with drastic flow regime change. It is suggested that Colebrook- White equation is applied in back calculation of pipeline equivalent roughness in order to avoid unreasonable value and analysis results show that results obtained from GERG equation are close to those from Colebrook-White equation when the adjustable parameter n=1 and the result tends to be stable when n≥6. The value n in GERG equation reflects flow regime change and the result is accurate when the value is consistent with Reynolds number which reflects flow regime change.