According to actual working condition of a tunnel engineering,the load distribution calculation model of the main drive bearing of the shield machine and isotherm contact elastohydrodynamic lubrication model were established.Through the numerical analysis,the oil film thickness and oil film pressure of the main drive bearing of the shield machine under the limit working condition and 99.9% working condition were obtained.According to the actual working conditions,the influence of different working conditions on the bearing oil film thickness and oil film pressure was analyzed,as well as the relationship between the roller load and oil film pressure and film thickness when the roller position was different.The results show that the oil film thickness and oil film pressure distribution of the main bearing are similar under different working conditions,both have secondary peaks.Under the same working condition,the maximum value of oil film pressure and film thickness decreases with the increase of roller load as the position of roller on the main bearing is different.At the same position,the maximum value of the two decreases with the increase of the bearing force of the main shaft.