The parameter matching of the hydraulically interconnected suspension（HIS） system has a critical effect on its dynamic performance. To improve the overall dynamic performance of the system，the global sensitivity analysis and multi-objective optimization are proposed for an anti-pitch and anti-roll HIS system. Firstly，a seven degree-of-freedom vehicle dynamic model is established in the frequency domain. Then，the riding comfort，stability，and anti-pitch and anti-roll performance of the vehicle are evaluated by stochastic road input. In addition，the global parameter sensitivity analysis of the HIS system is presented using the Sobol method to evaluate the influence of each parameter and find out the critical parameters of the HIS system. Furthermore，a multi-objective optimization procedure is proposed to optimize vehicle performance by the NSGA-II algorithm. The result illustrates that the linear loss coefficients of the damping valves on cylinders and accumulators have a significant influence on each performance index，and the interaction effect of some parameters has a great influence on vehicle anti-roll performance. After multi-objective optimization，the optimization result obtained by the weighted coefficient method shows that：the root mean square（RMS） value of sprung mass′s weighted acceleration is decreased by 20.94%；the RMS value of pitch acceleration is decreased by 12.95%；the RMS value of roll acceleration is decreased by 8.05%；the mean value of tire dynamic force RMS value is decreased by 11.17%. Through the global sensitivity analysis and multi-objective optimization，the overall vehicle performance can be improved significantly.