As the laser technology is developing in military applications,it becomes important to detect and warn the laser threat signal.The distribution of the scattering irradiance of 1.06 μm laser signal in atmosphere is calculated by using Mie scattering theory.Taking the laser range finder signal as an example,the influence of the laser threat source′s parameters (such as pulse energy,pulse width,threat source distance,etc) on laser scatter intercept radius is discussed.The result shows that the changes of source parameters have evident impact on laser scatter intercept radius.It is necessary to take them into account in test and use of laser warning equipments.