Abstract: A method of making fire-resisting synthetic boards including steps of dipping two pieces of fabric in a coating material prepared by mixing clay powder with a urea, water, a stabilizing agent, latex, sodium chloride, and a pigment; bonding the coated fabrics together by an intermediate bonding material prepared by mixing clay powder with urea, water, sodium chloride, and a stabilizing agent, so as to obtain a blank; drying the blank thus obtained in a kiln permitting the intermediate bonding material to form into a foamed structure and then surface treating the board thus obtained into a finished product.