In this paper the effects of stratospheric volcanic aerosols on longwave radiation budgets at the top of the atmosphere and on the surface and the infrared cooling rates in the atmosphere were investigated through radiative transfer calculations for different atmospheres under clear and cloudy conditions. It was found that the most pronounced heating role of the stratospheric volcanic aerosol occurs in the stratosphere. Compared with the effect of stratospheric volcanic aerosols on solar radiation,its effect on longwave radiation is relatively small.