This paper aims at Radiation characteristics of brightness temperatures over the Tibetan Plateau observed by the FY-3C/D Microwave humidity and temperature sounder (MWHTS) oxygen absorbing channels. To demonstrate the characteristics of the data over Plateau site, time series of monthly averages of the brightness temperatures are constructed for January, April, July, and October. The measured uncertainty distributions of brightness temperatures with frequencies centered at 118.75 GHz are investigated in terms of nonlinear-calibration inaccuracy, antenna pattern correction and angular-dependent cohesive noise mitigation. Data used in this study are collected for 2014 for one month in each season with humidity analysis is described in detail.