The dependence of the open-circuit voltage and internal resistance on the distance between the lens and solar cell is investigated in a concentrating photovoltaic system. The results show that the open-circuit voltage follows a Gaussian distribution function f(x) with that distance, and the internal resistance can be approximately described by 1 - f(x). Through experimental data fitting, we find that the maximum open-circuit voltage and minimum internal resistance will occur when the light is focused into the depletion layer of the solar cell. The light intensity dependence of the open-circuit voltage and internal resistance provide an indirect proof of the above conclusions. This is of great guiding significance for the design and research of current photovoltaic systems.