Prediction of dynamic performance will become very important in vehicle design to shorten development period, because counter-measures for component performance can be reflected into design drawings, and then validation period for a prototype can be shorten as much as possible for development of distribution vehicle like forklift truck. In this paper, we introduce a design methodology to apply multi-body dynamics, being coupled with mathematical power-line model, to engine-type forklift, and examine prediction accuracy for typical application, that is, traveling, lifting, tilting and combined working pattern. As a result, important design information for mobility, stability, working cycle time, can be simulated by this methodology, and the possibility for more effective development is confirmed.