Many researchers employed air or water for the active cooling of PV to achieve higher electrical efficiency, but additional energy consumption for air or water circulation may reduce the net power output or even the PV power output could not afford the energy consumption. Therefore, this paper provided a study on the electrical performance of PV panel with passive fin cooling of natural ventilation. Comparative study on PV panels with and without fin cooling was carried out with the consideration of the effect of PV panel inclination, solar radiation, air temperature and wind velocity as well as fin size on the electrical efficiency. The study showed that there existed a PV inclination resulting in the minimum electrical efficiency. Higher intensity of solar radiation led to lower PV electrical efficiency, and the efficiency dropped to the minimum around 11:40 during the day time. The PV electrical efficiency decreased in linear with the increasing air temperature. Every 10K decrease in air temperature led to the increase of electrical efficiency by 0.68% for both PV panels with and without fins. Every 1 m/s increase in wind velocity led to the increase of electrical efficiency by 0.08% and 0.14% for PV panels with and without fins, respectively. The effect of fin height on the electrical efficiency seemed to be very slight.