Drive axle is a key part of transmission system on the articulated vehicle. Its stability has a great influence on the performance of the truck. The gear transmission system of 45t articulated vehicle drive axle is taken as an example while the virtual prototype models of drive axle gear transmission system are established with Romax. The comparative simulation analysis of fatigue life of drive axle supporting bearing is performed through two means, the ISO281 and Romax Adjusted, which are methods for predicting bearing fatigue life. The results of simulation show that each supporting bearing has long life, low wear rate and long working time; the prediction of bearing fatigue life with Romax Adjusted agree with the actual work condition of bearing.