Abstract: For new quantum effects photo-detector array which has small dark current and high sensitivity, a gain adjustable readout circuit based on CTIA structure and sampling and holding circuit with correlated double sampling (CDS) technique was designed and fabricated in order to obtain a application of wide dynamic range. The 633 nm laser beam with radiation intensity tunable which is calibrated by a power meter shoots on the photo-detector cell one by one with a 50 m diameter facula. The test results show that the readout response voltage can reach to 55 mV and responsivity 3.67 E+08 V/W when biased voltage up to -3 V and radiation intensity 150 pW at 300 K and integration time 78 s. The test system is improved to reduce dark current further.