A complete infrared detector consist a detection device, readout circuit, and package structure and refrigeration component. At present, according to different application scenarios, the detection band range is constantly widening, the detection sensitivity needs to be improved, and the imaging speed requirements are accelerated, which put forward stricter and more complex index requirements for detector design. Among them, the readout circuit converts the detection optical signal into an electrical signal for transmission to the system, and is the key core module of the detector component. In this paper, an infrared focal plane detector reading circuit corresponding to a multicolor laminated quantum well device is designed, which is capable of detecting four-band signals at the same time and read them out at the same time, and there is no mutual interference between the detecting integrals of the four-band signals and the readout. The detector specification is 640×512, with a range of 50 μm, the signal of each band can be achieved by time integration, respectively adjusted. Adopting the work mode of integrating while reading out, the readout frame frequency can reach ≥50 Hz in four-band detection, the circuit noise ≤0.5 mV, the dynamic range ≥70 dB, power consumption ≤600 mW, which is an ultra-large-scale, low-noise, high-frame-frequency, high-performance readout circuits.