The front suspension of a car is taken as an example, according to the multi-body kinematics theory, making use of Lagrangian method, applying Virtual Prototyping Technology and software Adams/car , the front suspension math-model of a car is built, and deep simulation analysis for its alignment parameters is carried out. The result is consistent to the real experiment and the theoretical analysis. So this method is practicable to the optimizing design of manufacture and shortening its study periods.