A new type of microchannel heat sink is proposed to increase heat-transfer characteristic of traditional microchannel heat sink. The transverse microchannels are added compared to the traditional straight channels

and a layer of graphene that owns ultra high thermal conductivity is applied onto the lower surface of the plate of heat dissipation. Numerical analysis method is used to research on heat transfer performance of the traditional straight channel heat sink and the proposed new microchannel heat sink

and results show that the maximum temperature

the minimum temperature and the temperature difference of the proposed microchannel heat sink are decreased greatly by the adding transverse channel. As the heat flux is increased

reduction is increased. The addition of graphene layer mainly causes the significant reduction of temperature difference. Heat dissipation effect is further improved.