<p>The main bearing of tunnel boring machine (TBM), as the key load-carry component, was required high safety, stability, reliability under special working conditions. It is urgent to conduct structural design research that considers the vibration characteristics and fatigue reliability of the main bearing based on traditional main bearing design theories and methods. However, a large number of rows and complex nonlinear contact states of the main bearing rollers, it poses great challenges to the theoretical modeling of nonlinear dynamics and finite element numerical simulation. This paper explores the distribution law of the roller load and displacement of the main bearing based on the actual service conditions and typical connection structure characteristics of the main bearing, and obtains the mapping relationship between the structural parameters, contact stress and vibration displacement of the TBM main bearing. A novel structure optimizing design method for the main bearing that comprehensively considers vibration and structural fatigue performance is proposed. The optimization results indicate that the axial displacement of the main bearing has been reduced by 9.5 %, and the overturning angle displacement of the main bearing has been reduced by 8.6 %; The contact stress between the raceway and the positive thrust roller has been reduced by 3.5 %. The novel structure optimizing design method for the main bearing has significant engineering significance for improving the vibration performance and fatigue reliability of the TBM main bearing.</p>