In order to effectively evaluate the fatigue life of a light bus body structure,the multi-body dynamics body model was built with ADAMS,the accuracy of the model was validated by calibration with measurement data. Based on measured road load data,with comprehensive application of virtual iteration and fatigue life analysis methodology,the acceleration,displacement and force response signal which acquired at proving ground were reproduced,the internal forces between body and suspension were extracted,the fatigue life of body was calculated. The rounded corner of back row seat bracket reinforcing rib exists fatigue failure risk,which is consistent with failure result of road durability test. With improvement of material trademark,the body structure was ultimately passed the durability validation of proving ground,which has shown that the engineering practicability of this methodology. The practice has proved that the combination of virtual iteration and fatigue life analysis can effectively support the fatigue life evaluation of body structure,which has reasonable engineering reference value.