We analyze the phase functions of the sun aureole brightness in translucent clouds measured during the complex cloud experiment in the fall of 1996 in the Moscow region. The particle size-distributions V(r)/dr measured in cirrus are shown to be very stable, regardless of the optical depth and cloud form, both in shape and position of the maximum (radii of optically equivalent spheres R = 22 - - 25 mm). As a result, the cloud optical depth t and the total volume of particles Vе turn out to be related linearly, with the effective radii of particles Ref varying only slightly about the value of 35 mm. In altocumulus, the particle size distribution may be very stable within one cloud formation, while changing noticeably from case to case (the characteristic size is 3-5 mm). In cirro-cumulus Nn the particle size is even smaller - 1.5-3 mm and may change during several minutes. In the contrails living for about one hour, the mode of relatively large particles with the radius about 10 mm is formed.