The present disclosure relates to a superposed signal sampling apparatus, including: a signal receiving module, a signal extracting module, and a signal output module. The signal receiving module is used to receive a superposed signal. The signal extracting module is used to determine whether the received superposed signal is within a preset threshold range of a direct current signal; if the received superposed signal is within the threshold range, extract a previously received signal as a direct current signal to be output; and if the received superposed signal is beyond the threshold range, extract a currently received signal as a direct current signal to be output. The signal output module is used to integrate the direct current signal extracted by the signal extracting module, and then output the direct current signal. The present disclosure further relates to a superposed signal sampling method.