A device for diagnosing an audio circuitry, applicable to a mobile terminal and its earphone, both of the mobile terminal and its earphone comprising a microphone MIC circuit and a sounding circuit, the device for diagnosing an audio circuitry comprising: a MIC Circuit Diagnosis Module; and a Sounding Circuit Diagnosis Module; wherein: the MIC Circuit Diagnosis Module is configured for obtaining an amplitude and frequency of a sine wave signal sampled by a MIC circuit under test, determining whether the MIC circuit under test is qualified or not according to the amplitude and the frequency and outputting the sine wave signal, wherein the MIC circuit under test is the MIC circuit of the mobile terminal or the MIC circuit of the earphone of the mobile terminal; the Sounding Circuit Diagnosis Module comprises a converter circuit board with a MIC circuit and a processor; the converter circuit board is configured for sampling an analog signal output by the sounding circuit, converting the analog signal into a digital signal and sending it to the processor; the processor is configured for analyzing and processing the amplitude and frequency of the digital signal and determining whether the sounding circuit is qualified or not; the MIC Circuit Diagnosis Module is also configured for determining the MIC circuit is qualified when the difference between the amplitude and predetermined standard value is less than a first threshold value and a distortion of the frequency does not occur; characterised in that the MIC Circuit Diagnosis Module is also configured for adjusting the uplink gain of the MIC circuit under test until the difference is less than the first threshold value when the difference between the amplitude and predetermined standard value is greater than the first threshold value and less than a second threshold value, wherein, the number of times for adjusting the uplink gain of the MIC circuit under test cannot exceed a predetermined value. a MIC Circuit Diagnosis Module; and a Sounding Circuit Diagnosis Module; wherein: the MIC Circuit Diagnosis Module is configured for obtaining an amplitude and frequency of a sine wave signal sampled by a MIC circuit under test, determining whether the MIC circuit under test is qualified or not according to the amplitude and the frequency and outputting the sine wave signal, wherein the MIC circuit under test is the MIC circuit of the mobile terminal or the MIC circuit of the earphone of the mobile terminal; the Sounding Circuit Diagnosis Module comprises a converter circuit board with a MIC circuit and a processor; the converter circuit board is configured for sampling an analog signal output by the sounding circuit, converting the analog signal into a digital signal and sending it to the processor; the processor is configured for analyzing and processing the amplitude and frequency of the digital signal and determining whether the sounding circuit is qualified or not; the MIC Circuit Diagnosis Module is also configured for determining the MIC circuit is qualified when the difference between the amplitude and predetermined standard value is less than a first threshold value and a distortion of the frequency does not occur; characterised in that the MIC Circuit Diagnosis Module is also configured for adjusting the uplink gain of the MIC circuit under test until the difference is less than the first threshold value when the difference between the amplitude and predetermined standard value is greater than the first threshold value and less than a second threshold value, wherein, the number of times for adjusting the uplink gain of the MIC circuit under test cannot exceed a predetermined value. the MIC Circuit Diagnosis Module is configured for obtaining an amplitude and frequency of a sine wave signal sampled by a MIC circuit under test, determining whether the MIC circuit under test is qualified or not according to the amplitude and the frequency and outputting the sine wave signal, wherein the MIC circuit under test is the MIC circuit of the mobile terminal or the MIC circuit of the earphone of the mobile terminal; the Sounding Circuit Diagnosis Module comprises a converter circuit board with a MIC circuit and a processor; the converter circuit board is configured for sampling an analog signal output by the sounding circuit, converting the analog signal into a digital signal and sending it to the processor; the processor is configured for analyzing and processing the amplitude and frequency of the digital signal and determining whether the sounding circuit is qualified or not; the MIC Circuit Diagnosis Module is also configured for determining the MIC circuit is qualified when the difference between the amplitude and predetermined standard value is less than a first threshold value and a distortion of the frequency does not occur; characterised in that the MIC Circuit Diagnosis Module is also configured for adjusting the uplink gain of the MIC circuit under test until the difference is less than the first threshold value when the difference between the amplitude and predetermined standard value is greater than the first threshold value and less than a second threshold value, wherein, the number of times for adjusting the uplink gain of the MIC circuit under test cannot exceed a predetermined value.