The invention relates to a GPS synchronous time giving circuit, which comprises a GPS satellite receiving module, a phase discrimination module, a loop filter module, a voltage-controlled oscillation module, a frequency division module and a signal output end, wherein the GPS satellite receiving module is used for receiving pulses per second; the phase discrimination module is used for receiving the pulses per second and outputting error signals proportional to a phase difference according to the phase difference between frequency feedback signals outputted by the frequency division module and the pulses per second; the loop filter module is used for filtering a high-frequency component and noise in the error signals and outputting average component signals; the voltage-controlled oscillation module is used for adjusting the frequency for outputting correction signals according to the average component signals and outputting the correction signals via the signal output end; and the frequency division module is used for carrying out frequency division on the correction signals and outputting frequency feedback signals. According to the above GPS synchronous time giving circuit, high-precision synchronous sampling between sampling devices can be realized, and the clock inside each sampling device can be automatically corrected.