Curing behavior and structural property of an inorganic compound added urea-formaldehyde(UF) and urea-melamine-formaldehyde(UMF) were studied. In addition, tensile strength and formaldehyde emission of plywoods made of those resin binders were studied. Curing temperature and structure were not changed, but tensile strengths of plywoods manufactured both with a UF resin and a UMF resin were decreased slightly as increased amount of inorganic compound. Formaldehyde emissions from plywoods were reduced as increased amount of inorganic compound. Wheat flour as an extender was helped to reduce of formaldehyde emission. From the result of this study it might be estimated that using appropriate amount of inorganic compound and proper resin system can be strengthened bond strength and reduced formaldehyde emission.