With the increase of oil and gas wells with long horizontal section,coiled tubing with small outer diameter and large flexibility is more and more prone to spiral buckling locking in the downhole,so that it can not continue to run.Coiled tubing hydraulic oscillator can effectively reduce friction and drag,delay spiral buckling locking,and increase the running depth of coiled tubing,so it is widely used.According to the motion and force analysis of screw coiled tubing hydraulic oscillator in the working process,the axial force calculation formula was obtained.The grey correlation method was used to analyze the influence degree of various influencing factors on the axial force of coiled tubing hydraulic oscillator.It is found that flow rate,fluid density and rotor eccentricity have the greatest impact on its axial force.The example calculation shows that the maximum axial force of coiled tubing hydraulic oscillator increases with the increase of fluid density,flow rate and rotor eccentricity;the change frequency of axial force of coiled tubing hydraulic oscillator is independent of fluid density,and increases with the increase of flow rate and decreases with the increase of rotor eccentricity.