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Since 2000, China has launched four sun-synchronous ocean optical remote sensing satellites, Ocean-1A, 1B, 1C and 1D. The detection of sea surface temperature (SST) distribution and variation is one of the main tasks of Chinese ocean color and temperature scanner (COCTS), which is the main load of Ocean-1 satellite. Considering the detection of sea ice, typhoon and other meteorological elements over the ocean, the dynamic range of the actual water temperature detection channel is required to cover the temperature range of 200K to 320K. The variation of temperature in some ocean areas will lead to severe weather disasters, so SST detection channels need to meet the requirements of detection sensitivity and quantification accuracy. Objective: The purpose of this paper is to design the information acquisition circuit of infrared channel for COCTS according to the technical requirements, including the pre-amplifier circuit to amplify the weak signal of the detector, the AC amplifier which eliminates the basic level to improve the dynamic range, and the channel amplifier circuit which can realize the DC recovery and dynamic range adjustment of the signal. Method: Based on the study of the working mechanism of the photoconductive infrared detector used, and combined with the system composition and the characteristics of COCTS, in order to ensure that the contradictory requirements of high dynamic range and high sensitivity are met at the same time, the form and parameters of each stage amplifier circuit were determined on the basis of theoretical analysis, calculation and simulation. In order to achieve the stable reference level detection and single pixel signal detection of the whole field of view, the corresponding high-pass and low-pass filter are designed. The system performance of COCTS will be measured in the vacuum environment simulation laboratory, to verify the reasonability of information acquisition circuit design. Result: The results of the infrared radiometric calibration in the laboratory show that the dynamic range of the two infrared channels covers 177K to 327K and 173K to 324K respectively, and both meet the technical requirements of 200K to 320K. The noise equivalent temperature difference (NETD) of the two infrared channels in the whole dynamic range is between 20mK and 110mK. At the appraisal position of 300K, NETD has reached 21mK to 34mK, which is much better than the technical requirements of 0.2mK. Space test environment is more complex than the laboratory, and there are also some differences in measuring accuracy. The results of in orbit test show that the dynamic range of the two infrared channels is 186K to 328K and 185K to 326K respectively, and the NETD in the whole dynamic range is between 50mK and 110mK according to the window size of the selected target area. The performance is better than the technical requirements. Conclusion: The infrared channel can track the change of the blackbody signal on the satellite with the time and the surrounding environment changing, so the calibration coefficient of the infrared channel can be corrected in real-time. The expected goal of real-time radiometric calibration in orbit can be achieved. This lays a foundation for the quantitative inversion of SST, and can obtain and make high-quality global SST products.