On the basis of considering radial clearance and the changing of contact deformation when defect rolling element passing inner and outer ring, an intershaft bearing dynamic model with local defect rolling element was established under two kinds of supporting form. The vibration effect of different supporting form and different rotating direction of inner and outer ring were comparatively researched in this paper. The result shows that，the vibration amplitude of the supporting structure with the inner ring bearing in the high-pressure rotor and the outer ring bearing in the low-pressure rotor is bigger than the supporting structure with the inner ring bearing in the low-pressure rotor and the outer ring bearing in the high-pressure rotor；compared to inner and outer ring counter-rotating, the vibration amplitude of inner and outer ring co-rotating was bigger；although the impact amplitude was small and it was not conducive to find fault when inner and outer ring counter-rotating, it is more frequently that the defect attacks the rolling element, so under the same operating condition, the co-rotating intershaft bearing has a larger potential risk；the rotating frequency of cage was the main modulation frequency of intershaft bearing vibration signal, and compared to inner and outer ring co-rotating, the modulation effect of inner and outer ring counter-rotating was more intense.