The effect of ozone addition on combustion of Homogeneous Charge Compression Ignition (HCCI) engine was investigated to develop a OD physical model of combustion and to propose a predictive static model of combustion parameters. All parameters of the physical model were identified using a single-cylinder fueled with iso-octane running at constant engine speed (1500rpm) and equivalence ratio (φ = 0.3) but various EGR rates and ozone rates. Experimental data were used to validate the physical model. Results show that the OD combustion model yielded good results to capture combustion parameters like in-cylinder maximum pressure (Pmax), corresponding angle (CADpmax) and the crank angle degree when 50% of the fuel had burned (CA50). All these parameter have been found strongly dependent on ozone addition and EGR rate. Then, mathematical equations were developped presented to describe the static relation between combustion parameters and both EGR rate and ozone addition.