The invention discloses a method for predicting the assembly eccentricity of a high-pressure rotor of an aeroengine. According to the finite element analysis result of an ideal assembly model, a partof the high-pressure rotor is cut into an unstressed area and a seam matching area by an ideal plane; the unstressed area of the part is used as a remaining part, according to the error measurement result and the assembly phase of the part, the error of the remaining part is obtained by geometric analysis; the seam matching areas of the adjacent parts are combined into a combined part, consideringthe error measurement result and the assembly phase of the part, matching deformation is analyzed by a finite element method, the deflection of a free end face of the combined part is extracted as the part error; the newly formed combined parts and the remaining parts are regarded as rigid body parts with only pose error and no topographical error; and the assembly eccentricity of the rotor is solved by a rigid body error transfer method. The method can predict the assembly eccentricity of the high-pressure rotor more quickly and accurately by considering the seam topography error and the assembly deformation.