In the water-saving irrigation, the characteristics of sprinklered raindrops is an important standard of nozzles hydraulic performance. The paraments which can reflect the characteristics of raindrops mainly contain drop diameter, drop size distribution, drop velocity and raindrop kinetic energy, in all of this parameters, the raindrop diameter is the basis of other parameters studies. This paper makes accurate measurements of drop view, drop size distribution, equi-volumetric diameter and vertical velocity of raindrops by using 2D-video-distrometer. It also analyses the trend on raindrop equi-volumetric diameter affected by nozzle size and working stress, and establishes a model based on the relationship of raindrop equi-volumetric diameter and the vertical velocity. The results show that the equi-volumetric diameter of artificial rainfall sprinklers raindrop is ranged from 0 to 3mm and when the working pressure increased, the equi-volumetric diameter of raindrops decreased as the sprinklers size is not changed; on the contrary, when the working pressure is changeless, the equi-volumetric diameter of raindrops increased as the sprinklers size increased. According to the relationship model of equi-volumetric diameter versus vertical velocity of raindrops, it can get of good prediction of the vertical velocity which may provide a fundamental basis for kinetic energy calculation and establishing the mathematical models of erosion forecasting.