A method of absolute radiometric calibration for FY-2C infrared split-window channels by using sea buoy data and NCEP reanalysis data was introduced. In 2006， ten times remote sensing data were selected to obtain the radiometric calibration coefficients. The calibration results obtained from this new method were compared with the product brightness temperature provided by FY-2C. The results show that the biggest differences of the brightness temperatures at the top of atmosphere(TOA) obtained from these two suits of calibration coefficients are mainly located at the low surface temperature pixels， such as the top of clouds and snow covered areas， however， the calibration differences are small in the normal temperature pixels of land and sea surface areas， and the differences of TOA brightness temperature are mainly around 2K. This new vicarious calibration method can increase the calibration frequency and provide a methodological foundation for the real-time radiometric calibration of FY-2C infrared split-window channels.