In this paper, heat-releasing sheets made of AlN powder and acryl binder as thermoset were prepared using tape casting method. The crystal structure and morphology, the thermal properties as nonvolatile solid content and thermal conductivity, and the surface resistance of heat-releasing sheet were measured by using X-ray diffractometer, field emission-scanning electron microscopy, thermo gravimetric analyzer and laser flash instrument, and surface resistance meter. It was proved that thermal conductivity is greatly affected by the content of binder in heat-releasing sheet. Superior thermal conductivity above 3.5 W/mK and suface resistance were obtained at heat-releasing sheet with above 90% of AlN powder.