In this paper, theoretical and experimental studies were conducted on the cooling performance of a microchannel heat dissipation device with a manifold layer added. By adding 500 μm wide microchannels and manifold flow fields, the rheological properties of the cooling fluid were enhanced to improve the heat transfer performance. The size of the microchannel used for cooling was 40 × 40 × 5 mm, and was evaluated under a heat flux of 12.5-43.75 W/㎠ and a flow rate of 0.3-1.1 L /min conditions. As a result of the experiment, in the case of a microchannel heat sink of 500 μm compared to the existing heat sink, cooling was successfully performed under a heat flux condition of about four times