In this paper,we put forward a new control method for urban thermal environment based on the emissivity features,which discussed the atmospheric absorption characteristics of longwave radiation and the transfer process of radiation energy in atmosphere.We analyzed the radiation energy of wavelengths from 8 μm to 13 μm for soil,lawn,cement pavement,floor tile pavement,marble pavement and shrub.The results revealed that the maximum radiation energy is cement pavement at 34 ℃ and the least is the shrub at 21.2 ℃.Atmospheric absorption of radiation energy for cement pavement at 34 ℃ is maximal,so the atmospheric counter radiation effect is strongest.On the contrary,atmospheric absorption of radiation energy for shrub at 21.2 ℃ is minimal,and the atmospheric counter radiation effect is weakest.The radiation energy of cement pavement at 34 ℃ through atmosphere to outer space is most,so it has the strongest radiation heat transfer with outer space.The radiation energy of shrub at 21.2 ℃through atmosphere to space is least,it has the weakest radiation heat transfer with outer space.The urban thermal impact from high to low is: cement pavement at 34 ℃,marble pavement at 39 ℃,soil at 26 ℃,floor tile pavement at 27.9℃,lawn at 22 ℃ and shrub at 21.2 ℃.The study also shows that the urban thermal effect of land surface depends on itself temperature and emissivity.