During the course of present investigation

a method for simulating the rain in 3D terrain scene in the real time is proposed

using particle systems. The applicable attributes have been analyzed with reference to the rain particle system and the rain particles

in accordance with the basic principles of particle systems. Methodological approach includes the employment of feasible techniques or algorithms such as defining a cube outside the top of the view frustum as the generation shape of rain particles

using a point in pixels and a subsequent line as the shape of a rain particle

simulating the gravity influence in the course of rain particles' put down

replenishing continuously rain particles using particle groups and

testing the fall heights of rain particles in the real time etc. The results of experimentation have proved that this method is more effective in the representation of rain in 3D terrain scene which also found to be realistic at the time of satisfying basic need of real time interactive navigation.