The 480×6 cooled long wavelength infrared detector is a 480 row,6-stage TDI,high detection rate CMOS detector.The paper gives a detailed description of design procedure on the principle of low noise.It focuses on the problem how to reduce noise under the circumstance of guarantee ability of drive load.The experiment result demonstrates that system works well and has a comparably good noise characteristic.The RMS noise of the acquisition system is 1.20 mV and the SNR reaches over 55 dB under the irradiation of blackbody at 300 K.