Based on basic theory of structural modal analysis,a simulation analysis method for coupled vibration characteristics of the rotating assembly structure of two-stage fuel pump was established.A rotating assembly of a two-stage fuel pump,which is commonly used on civil aviation engine,was selected as the analysis object,and a 3-D finite element model for the analysis of its coupled vibration characteristics was established based on the general finite element software platform.Considering the actual contact relationship between parts within working speed range,on the premise of linear solution,the mass-stiffness distribution of the parts in contact was made become the boundary condition of each others vibration,and at the same time,the influence of stress state between the parts in contact on the vibration characteristics was also taken into account.By using the model,the coupled vibration modes and frequencies of the rotating assembly structure under all rotating speed conditions were calculated.And combined with its working conditions,the Campbell curve was figured out.The results show the affect rules of the external loads on the coupled vibration characteristics of the rotating assembly,and the vibration weak areas.In order to improve the overall reliability of the two-stage fuel pump,some structural and maintenance measures were given.