This paper focuses on the influence of the illumination of CdS/ZnTe solar cells with different ZnTe thin film thicknesses. The devices were analyzed through current-voltage measurements. The values of the open circuit voltage (VOC) and the short circuit current density (JSC) depend on the substrate and source temperatures. The JSC is observed to decrease from 224 A/cm2 to 95 A/cm2 with increasing the source temperature from 560 ℃ to 600 ℃, while the VOC increases from 0.41 V to 0.54 V, respectively. The value of VOC increasing from 0.68 V to 0.76 V, but JSC decreasing from 760 A/cm2 to 500 A/cm2, when ZnTe thin film thickness increasing. Besides, the impact of the light intensity on the photovoltaic parameters of the CdS/ZnTe solar cells with different ZnTe thin film thicknesses was analyzed. The increasing in the light intensity from 20 mW/cm2 to 100 mW/cm2 rise the VOC from 0.67 V to 0.76 V tending further to saturation. Regardless of ZnTe thin film thickness, η increases logarithmically with the light intensity, but for the Jsc is observed linear dependence. The Rs increases with the increasing ZnTe thin film thickness, but decreases with the increasing of light intensity. Also, the Rsh, changes under changing the ZnTe thickness and the light intensity.