A low noise real-time imaging data acquisition system based on a 512×8 dual band TDI IRFPA is designed. According to the characteristics of internal circuits and output analog signals, a low noise collection circuit composed of bias voltage, drive circuit, A/D conversion circuit and digital signal processing module etc is designed. It is found in the noise test that at the room temperature of 26 ℃, the noise of the circuit is 0.02 mV to 0.18 mV. For the integration time of 300 μs, the noise voltage of each shortwave infrared detector element and that of each mid-wave infrared detector element are 2.5 mV to 4.5 mV and 8 mV to 10 mV respectively. Their signal-to noise ratios are 52 dB to 57 dB and 43 dB to 48 dB respectively. The test results show that the system has good noise characteristics and can meet the requirements of practical engineering application.