People are exposed to whole-body vibration involving multiple directions during daily life especially travelling in vehicles. This study carries out experimental research on human response to dual-axis lateral and roll vibration. Random and sinusoidal vibration defined at 1 Hz are employed as the stimuli. Corresponding apparent inertia and root mean square of human response are measured to investigate the effect of phase difference as well as the vibration intensity. As a result, the symmetrical effect of the phase difference on the human response is detected. The intensity of roll and lateral vibration shows opposite effects. Partial coherence analysis is conducted, and the dominance of lateral vibration is confirmed. Hence, to improve the ride comfort, the lateral vibration needs a higher priority to be controlled compared to the roll one. The compensation effect of the roll vibration provides an effective way to reduce human response around the resonance frequency as long as the magnitude of it is carefully controlled.