It is carried out a series of synchronous measurnients of the irradiance scintillation and the extiction of a He-Ne laser beam propagating through a real turbulent atmosphere over complex terrain. The relationship between the statistical properties of the irradiance scintillation, such as the scintillation index, the probability distribution and the power spectrum, and the extinction was analysed. There is certain relationship between laser irradiance scintillation and irradiance extinction in a real atmosphere.