The effect of Cs+ ion and Rb+ ion in the molten salt of different proportion on the single panel fire-resistant glass is discussed in this paper. The single panel fire-resistant glass was prepared by the method of ion-exchange, with proper amount of additives and adding KNO3 and CsNO3 , KNO3 and RbNO3 as the main part of molten salt. The proportion of the molten salt was changed separately, a contrast test was performed to measure the flexure strength. The results indicated that the flexure strength of the single panel fire-resistant glass increased firstly and then stabilized as the ratios of w(CsNO3)/w(KNO3) and w(CsNO3)/w(RbNO3) increased respectively. With the ratio of w(CsNO3)/w(KNO3) =1.5%, the mechanical property of the single panel fire-resistant glass was proper and the maximum flexure strength was 274 MPa. In the case of RbNO3, the flexure strength of single panel fire-resistant was 244 MPa with the ratio of w(CsNO3)/w(KNO3) = 0.3%. According to the research, it is found that the method of ion-exchange of Cs+ and Rb+ into plain glass to prepare single panel fire-resistant glass is feasible, the sample melted under the condition of 1 hour and 780 without any trace of thermal explosion.