Abstract: In view of the difficulties in bearing connection modeling for the dynamic strength analysis of long-life small biax solar array drive mechanism (BSADM), a method for determining the bearing stiffness under assembly state at the design stage based on the previous product test data and theoretical formula was proposed and implemented. The dynamic strength model of whole machine was established, and the calculated modal frequency was consistent with the experimental results, thus, the simulation accuracy was improved. Subsequently, the strength analysis under dynamic loads during lunch and deployment process was carried out, and the results of the structural dynamic stress of whole machine under random vibration and impact loads were also given. The proposed research may provide a reference for the safety evaluation of whole machine’s dynamic strength in the design stage.