Abstract: Cavitation characteristics and stress characteristics are powerful guarantee for stable operation of axial flow pump.It is of great engineering significance to study stress characteristics under cavitation conditions.Taking axial flow pump as research object，through sequential fluid solid coupling method，CFD analysis results of steady cavitation flow in axial flow pump were taken as main mechanical boundary conditions and finite element method was adopted，stress characteristics of impeller under cavitation，cavitation initial cavitation and severe cavitation were analyzed.Results showed that maximum equivalent stress of axial flow pump impeller occurred at blade root near outlet edge.Without cavitation and cavitation initiation，stress distribution was basically the same.Maximum equivalent stress was about 36 MPa.When cavitation was serious，high stress region was smaller than the first two cases.Stress distribution in the blade was analyzed by taking different sections.It was found that there was a high stress area at two ends of pressure surface area and it decreased to middle of blade when cavitation was serious，and suction surface only has a high stress area on side of exit side.Distribution of stress along intersection of blade pressure surface root was similar to that of cavitation，but distribution on intersection of suction surface root would change from approximate linear distribution to parabolic distribution.