The measurements of solar radiation and meteorology were carried out at Yucheng and Luancheng Stations in North China during 2005-2006. Based on the analysis on the observation data, an energy relation between internal energy of the atmosphere and the surface solar global radiation, the absorption of atmospheric substances, the scattering of substances, the moving energy of atmosphere, the net radiation is developed. The variation of “monthly mean” of surface air temperature at 2 stations is simulated by using the empirical model, the maximum and minimum biases between the calculated and observed surface air temperature are 3.84 and -4.05℃ for “monthly mean”, respectively, and less than 0.36℃ for “annual mean”. The sensitivity calculation shows that the surface air temperature is most sensitive to the variation of net radiation, then to the changes of the scattering of substances, the absorption of atmospheric substances, the moving energy of atmosphere and solar global radiation. The increase of 5% contributed by individual factor, net radiation, the scattering of substances, the absorption of the atmospheric substances, the moving energy of the atmosphere, solar global radiation can cause the changes of surface air temperature by 0.93, -0.40, 0.23, -0.20, -0.12℃, respectively. To study the change of surface air temperature, it is necessary to consider the roles of greenhouse gases (such as CO2, water vapor, and O3). Meanwhile, it is also important to consider the absorption of other substances, the scattering of substances (in gases, liquid and particle phases), the changes of the compositions and characteristics of the Earth’s surface, the changes of surface wind velocity, and solar global radiation, especially the net radiation.