A front-end measuring system of an automatic external defibrillator, comprising: two electrodes; a carrier wave driving circuit configured to amplify a generated alternating current signal and output an amplified alternating current signal to the two electrodes; a sampling circuit that comprises at least one sampling channel, wherein the at least one sampling channel is a shared sampling channel, the shared sampling channel is a measuring channel shared for measuring at least two different kinds of measured parameters, the measured parameters are selected from a patient impedance, an ECG waveform data, and a pace pulse, the shared sampling channel comprises a difference amplifier and an analog-to-digital converter, two input ports of the difference amplifier are coupled to the two electrodes respectively, and an output port of the difference amplifier is coupled to the analog-to-digital converter, the analog-to-digital converter is configured to convert an input analog signal to a digital signal by sampling the input analog signal with a predetermined sampling rate and then output the digital signal, the predetermined sampling rate of the analog-to-digital converter is greater than or equal to a maximum sampling rate of the at least two different kinds of measured parameters measured with the shared sampling channel; and a processor, coupled to the sampling circuit, which is configured to generate the alternating current signal, output the generated alternating current signal to the carrier wave driving circuit, receive the digital signal output by the sampling circuit, and extract a digital signal according to a sampling rate and an accuracy required by the measured parameters. two electrodes; a carrier wave driving circuit configured to amplify a generated alternating current signal and output an amplified alternating current signal to the two electrodes; a sampling circuit that comprises at least one sampling channel, wherein the at least one sampling channel is a shared sampling channel, the shared sampling channel is a measuring channel shared for measuring at least two different kinds of measured parameters, the measured parameters are selected from a patient impedance, an ECG waveform data, and a pace pulse, the shared sampling channel comprises a difference amplifier and an analog-to-digital converter, two input ports of the difference amplifier are coupled to the two electrodes respectively, and an output port of the difference amplifier is coupled to the analog-to-digital converter, the analog-to-digital converter is configured to convert an input analog signal to a digital signal by sampling the input analog signal with a predetermined sampling rate and then output the digital signal, the predetermined sampling rate of the analog-to-digital converter is greater than or equal to a maximum sampling rate of the at least two different kinds of measured parameters measured with the shared sampling channel; and a processor, coupled to the sampling circuit, which is configured to generate the alternating current signal, output the generated alternating current signal to the carrier wave driving circuit, receive the digital signal output by the sampling circuit, and extract a digital signal according to a sampling rate and an accuracy required by the measured parameters.