For increasing the efficiency of CdTe/CdS solar cells, it is important to measure the current-voltage and capacitance-voltage characteristics and then carry out a numerical simulation based on electronic measurement of CdTe and CdS thin films. In this paper, the capacitance-voltage characteristics were measured in the frequency range from 50kHz to 1MHz. The carrier concentrations of the absorber layer and the space charge region width were calculated. The dark current-voltage characteristics of the CdTe solar cell were measured in the temperature range from 220K to 300K. The saturated reverse dark current density J0 and the diode ideal factor A of the solar cells were obtained. The relations of J0 and A with temperature were discussed. The results show that the capacitance-voltage curves has two peaks and the intensities and positions of the peaks are dependent on measurement frequency. The results are simulated and explained with the multi-junction model. With decreasing temperature, the saturated reverse dark current decreases from 10-6mAcm-2 at room temperature to 10-7mAcm-2 at 220K, and the diode ideal factor rises from 2.13 at room temperature to 9.95 at 220K.