This paper studies a two-body wave energy converter which is a two-degrees-of-freedom oscillating point absorber. The two-body wave energy converter oscillating in heave with a floating body of variable geometry connected to a submerged body is designed for the Australian ocean wave conditions with excitation frequency ranging from 0.08 Hz to
0.12 Hz and wave height of 1 m. Taguchi method has been applied to investigate the system model parameters’ influences on the average power output where the main input variable parameters are the power take-off stiffness and damping coefficients, submerged and floating body geometries, depth of the submerged body, floating body draft, diameter and geometry inclination angle. ANSYS AQWA is employed to obtain the hydrodynamic parameters in the regular wave conditions in order to calculate the output power. Both linear and non-linear dynamic models of the two-body wave energy converter will be analysed and simulated in both the time and frequency domains. The Power-take-off stiffness coefficient and submerged body geometry have been identified to be the most important parameters in influencing the average power output in the studied frequency range.