Novolacs were successfully synthesized using oxalic acid as the catalyst in a self-designed device based on a domestic microwave oven. The fundamental characteristics of the synthesis of novolacs under microwave irradiation (MI) were investigated, and the properties of the resins polymerized and dehydrated under microwave irradiation and conventional heating (CH) were analyzed comparatively. The results show that MI reduced the polymerization and dehydration time greatly; and that the resins polymerized and dehydrated under MI presented longer flow distances (i. e. , higher flowability) and shorter cure time than those obtained under CH.