The present paper is based on field investigation and measurement of rill erosion processes at Rangamati Experimental Station (Medinipur, West Bengal in India). In rill experiments, three different natural rills were studies in field for understanding of the dynamics of soil erosion processes of a rill catchment area. Geometric and morphological characteristics of each rill catchment area were analyzed. Results showed the widening, deepening and extended of rills because of sidewall sloughing, knick-points and head-ward erosion during surface runoff process. Progressive increases of rill volume were observed in the upper, middle and lower catchment with the change of time. Rill area has increased by runoff processes of 4.2 % and 6.8 % for Rill-A and Rill-B respectively. These processes are depends on surface coverage, soil texture, slope gradients and runoff velocity.