A 10 m center-spacing infrared readout circuit with 2×2 pixel binning function is introduced. This circuit combines the characteristics of high resolution and high frame rate, and can meet the requirements of both long-distance search and short-distance tracking and recognition application modes. Before pixel binning, the array specification of the readout circuit is 1280×1024 with a pixel center-spacing of 10 μm and high spatial resolution, suitable for short-distance tracking and recognition mode. In the pixel binning mode, the array specification changes to 640×512, pixel center-spacing changes to 20 μm, and the sensitivity is high, which can be used in long-distance search mode. In addition, the proposed circuit adopts a serial input control method and has functions such as integrate then read (ITR)/integrate while read (IWR) working mode switching, 4/8 channels selectability, flipping and power consumption control. This circuit is designed with GF 0.18 μm process. The simulation results show that the achieved maximum frame frequency by the readout circuit is doubled in the pixel binning mode.