This study represents a numerical investigation of the compatibleness of mini-channel heat sink with high heat dissipation rate and the fluid flow patterns inside mini-channels for integrating secondary channel (or interconnector). A novel shape, rectangular fin with rounded ends, mini-channel heat sink was proposed to compare with the thermal performance of rectangular finned and oblique finned mini-channel heat sink. In this study, hydrodynamic characteristics of water as coolant was considered in the single-phase regime, and the flow was considered under laminar flow conditions at Reynolds numbers range of 150 to 1050 with a constant heat flux of 200 KW/m2 at the bottom surface of the mini-channel heat sink. Thereafter, a Performance Evaluating Criteria (PEC) was implemented for all cases to compare with the conventional mini-channel heat sink. The results showed that the overall Nu number for newly proposed rectangular fin with rounded ends shape mini-channel heat sink increases slightly with Re number when compared with the conventional mini-channel heat sink. The slight increment of Nu number was recorded at Re = 1050 for the newly proposed mini-channel heat sink up to ∼8% as compared to the conventional parallel flow mini-channel heat sink.