Since today’s engineering design is too complex and sophisticated, modelers have difficulty modelling a simulation models with good prediction. Complex engineered system has a large amount of uncertainties that even modelers can’t figure out. In this paper, model calibration method with bias is introduced to deal with the unrecognized uncertainties. To confirm the efficiency of this method, cantilever beam model is calibrated as a case study. As a result, the validity of cantilever beam model is proven.