Abstract: With the increased demand for long-range imaging systems such as remote sensing and satellite imaging, scanning type infrared sensors have been deployed extensively. To alleviate the problem of relatively poor SNR that would affect the image quality, a readout circuit with a time-delayed integration (TDI) technique was proposed and described. The readout circuit consisted of capacitor trans-impedance amplifier (CTIA) pixel circuits, paralleled TDI stages, multiplexer, and output buffer. CTIA based analog front-end circuit with optional gain and less than 0.3% nonlinearity was designed for processing large range photocurrent. The chip was manufactured with a 0.35 μm CMOS process and occupied an area of 1.3 mm×20 mm. With the 5 V power supply, the power consumption was less than 60 mW. To evaluate the function of the 1024×3 TDI readout circuit, different voltages were injected into three terminals and the output from the TDI stage was captured. The measurement results validate the proposed design successfully.