Abstract: Because of strong adaptability of road condition and small turn radius, mine articulated four-wheel drive vehicle was widely used in the mine auxiliary transportation. But high malfunction rate and low reliability of its bridge structure seriously affected its performance of operation. Through the analysis of bridge structural features and experiment data acquired from vehicle bench tests, the excess temperature of bridge bearings caused by high speed rotation was proved to be the reason leading to the malfunction. The method of increasing mounting clearance and replacing with bigger clearance bearings were adopted to improve the bridge structure. The experiment result showed that the situation of bearing temperature rising was alleviated effectively after the alteration. Through the structural modification, the reliability of bridge structure was improved and service life of vehicles could be extended.