Development of a passive anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) with the advantage of improving vehicle directional stability and handling quality is presented. A 7 degrees-of-freedom full car model and a 20 degrees-of-freedom anti-pitch anti-roll hydraulically interconnected suspension model dynamically coupled together through boundary conditions are developed and used to evaluate vehicle handing dynamic responses under steering/braking maneuvers. The modeling of mechanical subsystem is established based on the Newton's second law and the fluid subsystem is modelled using a nonlinear finite-element approach. A motion-mode energy method (MEM) based on the calculation of the motion-mode energy is employed to investigate the effects of an anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) system on vehicle body-wheel motion-mode energy distribution. The performance of AAHIS system and its contribution to the vehicle body-wheel motion-mode energy distribution are demonstrated under combined steering and braking maneuvers. The dynamic response of AAHIS system shows enhanced handling and ride performance as well as improved vehicle anti-roll and anti-pitch properties.