The invention discloses a green brick of a one-step sintered glass-ceramic composite board. The green brick comprises a green body layer and a glass-ceramic frit layer from bottom to top, wherein the glass-ceramic frit layer is formed by applying a glass-ceramic frit particle suspension liquid formed by mixing glass-ceramic frit particles and a frit particle binding agent on the surface of the green body layer; and the frit particle binding agent comprises the following components in percentage by mass: 5.5-6.5% of cellulose thickener, 2.5-3.2% of white carbon black, 1.1-1.4% of defoaming agent, 1.2-1.8% of dispersing agent and the balance of solvent. By using the green brick, glass-ceramic frit particles on the surface cannot be taken away by a draught fan at a preheating zone when being sintered, so that the waste is avoided, and the defect rate of glass-ceramic composite board products is reduced.