Granular material when subjected to shearing or vibration tends to separate or unmix to form the zones of different sizes. This phenomenon holds a significant implications wherever granular materials are involved, spanning natural occurrences like landslides to industrial process such as power mixing, pharmaceuticals and agriculture. In this study, Discrete Element Method (DEM) was employed to investigate the effect of particle size distribution on the size segregation in a bi-disperse flow. A periodic box with periodicity along flow (x) and lateral (y) directions is utilised to simulate the infinitely long and wide granular flow. The angle of inclination was changed in the range 24–30° allowing for the observation of the segregation across different flow regimes. While the size ratio of the granular system influences the segregation, the present study focuses on particles sized 8 and 4 mm, with size ratio of 2. DEM simulation clearly demonstrated the occurrence of segregation. Maximum segregation was observed at the lowest angle; however, segregation occurs faster at the higher angle.