The thermal issues of Chip-On-Film (COF) packages are becoming increasingly important for high-pin count chips, whose performance is becoming increasingly limited by the maximum power that can be spread without exceeding the maximum junction temperature. This study conducts a numerical investigation to investigate the relationship between power dissipation and the surface temperature of the thermal chip in COF applications. This study develops an ANSYS finite element (FE) model to simulate the junction temperature and temperature distribution within the COF package under various boundary conditions. Based on an effective methodology of equivalent models for thermal conductance, comparing the simulation results with the reference reviewing confirms the validity of the numerical model. Several parametric studies reveal the effects of various configurations of the thermal model. This study also analyzes the thermal resistance at the junction of the package. Results show that the natural convection of the COF package with thermally conductive tape (TCT) achieves a cooling function that keeps the junction temperature of the COF package under 85°C without using a fan. The FE models in this study have enormous potential to quickly assess the thermal limits of many future COF packages and their variations.