With the development of force metrology within superlarge range,force transfer system with a superlarge range has become a hotspot in the field of force metrology recent years. An uncertainty calculation model of the buildup system with a superlarge rangeconsidering the influence of the buildup structure was developed. A 60 MN buildup system was calibrated and its uncertainty was evaluated and verified. The researchresultsshow that the deformation of the buildup structure would induce indication error in the buildup system. The uncertainty component induced by the indication error is larger than that induced by the force transducer,whichis the main component in the combined uncertainty of buildup system with a superlarge range. In the evaluation, the influence of this component should be fully considered; when extrapolating the indication error and its uncertainty to full range, the power function should be used to perform the curve fitting and extrapolation of the buildup system indication error and its uncertainty, which will guarantee thatthe extrapolation results are accurate and reliable.