Abstract: Tropospheric duct could make electromagnetic waves achieve over-the-horizon propagation with lower attenuation and also leads to radar blind areas, accompanies by interference and reduces the performance of radar and radiocommunication systems. Therefore, it is meaningful to probe and retrieve the parameters of the marine tropospheric ducts in real-time. Recently, the inversion of tropospheric ducts from radar clutter becomes a hot spot of research. Radar sea clutter power over propagation path is regarded as the main input information, and its random characteristics greatly affect inversion results. This paper makes some study on the distribution characteristics of radar sea clutter power for the tropospheric duct experiments which are carried out in Bohai Sea during 6-8,2011 and 7-11, 2012 contributing inversion Comparing the probability distribution density of experimental data with distribution models show that the micro wave radar sea clutter power over propagation path does not meet Rayleigh distribution, but log-normal distribution.