Abstract Polycrystalline CdTe solar cell performance under high-intensity light irradiance was studied. The short-circuit current density and the open-circuit voltage were increased linearly and the fill factor and the efficiency of CdTe solar cells were decreased with increased light irradiance intensity, respectively. Analytical analysis was carried out to analyze the factors which induced the decreased fill factor. It was found that under one-Sun light irradiation, the series resistance of both the CdTe and the front electrode (F-doped SnO2, FTO, sheet resistance of 14Ω/sq) films contributed comparably to the series resistance. Under high-intensity irradiance of 25.9 Suns, the resistance of the CdTe layer was decreased to one hundredth value of that under one-Sun irradiance, while the resistance of the FTO remained unchanged. The experimental results clearly demonstrated that the electrical resistance of the FTO electrode is the limiting factor for the CdTe cell efficiency working under concentrated light irradiance.