Abstract: By taking cylindrical nozzle used for descaling in pipelines as research object, the fluid field of nozzle is simulated by Fluent software. The flow characteristics of nozzle jet are analyzed by changing the jet pressure, impact angles, environmental media and target distance. The simulation results illustrate that the maximum impinging pressure and shear stress of target surface become larger with higher jet pressure, and presents a linear relation. The jet cleaning has preferable performance when the impact angle is equal to 〖60〗^°. Under the two conditions of non submerged and submerged jet, different hydraulic parameters correspond to an optimum target distance. The cleaning ability of nonsubmerged jet is better than that of submerged jet when the jet pressures are the same. The results provide a theoretical basis for the application of pileline water jet cleaning engineering.