•Fatigue life analysis and structure optimization of the conveyor belt bedplate of the belt dryer.•The influence of the polygonal effect of the chain drive on the motion trajectory of the conveyor bedplate is analyzed.•The stress experiment was carried out on the conveyor belt bedplate, and the reason for fracture was analyzed.•The proposed calculation method provides a reference for the fatigue life analysis of the critical components of the belt dryer. The chain drive conveyor belt (CDCB) of the belt dryer is prone to generate impact load during operation, and the conveyor belt bedplate (CBB) will cause fatigue damage and fracture. This study presents an approach for calculating fatigue life, which combines the automatic dynamic analysis of mechanical systems (ADAMS), finite element analysis software (ANSYS), fatigue analysis software (FE-SAFE), and experimental stress analysis. The virtual prototype model for simulation of the CDCB is established, and its motion stability, contact impact force and motion trajectory are analyzed. The study shows that the chain drive polygon effect will cause periodic changes in velocity, and the motion trajectory has very good similarity. The stress experiment results show that the stress was considerable during the chain drive meshing process. The finite element analysis results show that the maximum stress of the old CBB is higher than the yield strength of the material, and the equivalent stress of the new CBB is lower than that of the old CBB. The area of the maximum stress of old CBB presents a fracture, which indicates the fatigue failure of the old CBB. The finite element calculation results were imported into FE-SAFE for fatigue life analysis, which compared the fatigue cycle number and safety factor of the old CBB and the new CBB. The results show that the new CBB can extend the service life of the belt dryer. The proposed analytical method for fatigue life is simple and effective and can serve as a reference for the fatigue life analysis of the key components of the belt dryer.