Abstract: The brightness temperatures between the measurement by the ground-based 12-channel microwave radiometer and that computed by the radiative transfer theory are compared. The data are measured in sunny day in September 2006. The results are as follows. The standard deviation of Tb in 51.250 GHz is 3.8 K, which is the maximum. The values from other channels are all less than the value in the 51.250 GHz. The bias values of Tb in 51.250 GHz and 52.280 GHz are larger than 1.0 K. The bias values in the other channels are less than 1.0 K. The slopes of the Tb fitting line are 0.66 and 0.7 in 52.280 GHz and 53.850 GHz, respectively. The slopes of other channels are larger than 0.8.  The temperature profile measured by the groundbased 12-channel microwave radiometer are compared with that measured by the Radiosonde from September 2005 to August 2008 in Bejing. The difference is increasing with the height. The measurements are analysed in terms of four seasons. From 0 to 10 km (with the heights from 8 km to 9 km excluded), the difference in Summer is larger than any of those in all other seasons. From 0 to 2.750 km, the difference in Spring is larger than in all other seasons. From 2.750 km to 3 km, the difference in Winter is larger than in all other seasons. From 3 km to 9 km, the difference in Autumn is larger than in all other seasons. There exists clear difference between the temperature profile measurements in sunny day and in cloudy day. The slope in sunny day is larger than that in cloudy day, which may be due to the sample number for the comparison.