A computer model capable of generating stylized light rain and heavy rain for cartoon animation is presented. How to analyze and extract the static and dynamic structures associated with trajectories of raindrops from hand-drawn cartoon series is shown at first. Based upon those structures, how to generate their skeletons and control dynamic behaviors of those skeletons is also shown. The single pass is used in the light rain model and the multiple passes are used in the heavy rain model, and in the later case the effects is enhanced by animating a cycle of drops hitting the ground.Due to the stochastic control mechanism used in the model,the resultant effects avoid the mechanical look that may cause by using repotitive cycles in hand drawn animation.To suggest mood,animators have to drfferent series with different timing and orentation of raindrops,while by varying a few parameters. the model can achieve the same results great ease.The method is also able to generate both 2D and 3D cartoon raindrops for animation.