Under vacuum conditions, the air is scarce and can not be used in the usual heating method. In order to solve the problem of heating of wood during vacuum drying, high frequency heating is used to vacuum drying. High frequency vacuum drying can eliminate the surface hardening cracking in normal pressure, and the pressure difference between high frequency vacuum drying wood and surface is relatively large. Under the action of pressure gradient, the moisture is quickly moved to the surface, and can increase the drying rate, shorten the drying time and reduce the operating cost. In addition, under the condition of low pressure, oxygen is scarce, and the material has little change due to the thermal effect and oxidation. It can keep the natural color of the material.