Abstract: As an effective device characterization method, the measurement of quantum efficiency (QE) can be tremendously informative about different structures of thin-film solar cell.While the results may be different if the solar cells are tested in different conditions. The QE of CdTe and perovskite thin film solar cells with different structures were measured in direct current (DC) mode and alternating current (AC) mode. The results show that the quantum efficiency of CdTe solar cells is affected by test frequency and lighted time. There is more effect of the results of perovskite thin film solar cells than CdTe thin film solar cells by frequency because of its device capacitance characteristics.