The thermal condition plays an important role in the final thickness distribution and in the mechanical behavior of the Polyethylene Terephthalate (PET) bottle obtained from the stretch blow molding (SBM) process. A complete 3D modelling of the heating stage during the SBM process under industrial condition is very time-consuming. Based on a simplified approach to quickly achieve the numerical simulation of the preform heating, an optimization procedure is proposed to adjust the settings of the infrared lamps by comparing our simulation results to the target temperature profile. In this numerical approach, the radiation source is simulated by using a model for intensity of the incident radiation and the Beer-Lambert law. On the other hand, the ventilation effect under industrial conditions is taken into account by modelling the forced convection around a cylinder. The infrared (IR) flux and ventilation effects are implemented as thermal boundary conditions in COMSOL software for a 3D computation of the thermal problem for the preform only. Since the simulation has a very reasonable computational time, an optimization procedure can be generated to adjust the setting of IR lamps. This optimization tool provides quickly a first set of parameters to help industry to obtain the desired temperature profile.