A specific mathematical model to obtain the parameters of steering wheel alignment for large wheeled harvesters was proposed in light of multi-body dynamics technique. A comparison between the proposed model and the traditional ones was made in terms of the optimization design of steering geometry and the performance of steady-state cornering response. Results showed that both models could reach a similar computing value in the small range of steering angles. However, for large steering angles, the proposed one was more appropriate to express the steering characteristics. Through theoretical analysis and experiment validation, it was limited to adapt traditional simplified bicycle model to depict handling stability of large wheeled harvesters. Therefore, the proposed model demonstrated its unique accuracy in the calculation of parameters of steering wheel alignment for large wheeled harvesters.