Submesoscales have received little attention in the north Bay of Bengal(nBoB). In this study, the spatiotemporal characteristics of submesoscales and its dynamic mechanisms in the nBoB are investigated by the output from a high-resolution MITgcm LLC4320 simulation. The results show that the submesoscales in the nBoB exhibit the pronounced seasonality and geographic variability. The head (region A) and central basin (region B) of the nBoB are identified as two typical spots of submesoscales via analyzing relative vorticity and submensoscale kinetic energy(KE). Seasonally, the submesoscales in region A are much strongest during spring. Compared with region A, submesoscales are more energetic in winter and late summer than spring and fall in region B. The submesoscales in regions A and B are highly correlated with only mesoscale strain rate (MSR) and with the combination of mixed layer depth(MLD) and MSR, respectively. The energy analysis suggests that the baroclinic instability is the dominant generation mechanisms of submesoscales in the nBoB during winter and summer. During spring period, the prevalent submesoscale KE reservoir in region A are fueled by wind forcing, buoyancy conversion, and the forward KE cascades from the mesoscale processes, and dissipated by the inverse KE cascades from the submesoscales to the largescale processes, highlighting the importance of barotropic instability.