Enhanced thermal performance is increasingly vital for the power module in high capacity application. However, the presence of multiple layers and high thermal resistance in the power module impedes the reduction of junction temperature. In this paper, the concept of power module with an integrated aluminum nitride (AlN) ceramic heatsink is proposed to achieve low thermal resistance packaging. The thermal simulation results demonstrate a significant 64% reduction in thermal resistance between the traditional power module and the power module with an AlN ceramic heatsink. Besides, the detail and straightforward manufacturing process of the ceramic heatsink is introduced. The junction temperature between AlN ceramic heatsink and conventional power module under different voltage, current, output power and fluid velocity are comprehensive compared in the experiment. It is observed that a maximum reduction of 37 ℃ in junction temperature is achieved, the maximum junction temperature difference between the traditional and ceramic heatsink power modules is respectively 42 ℃ and 18 ℃. The enormous advantages of the power module with an integrated AlN ceramic heatsink in thermal enhancement is verified.