The effect of sodium silicate module(0.3、0.6、0.9、1.2、1.5、1.8、2.1、2.4 and 2.7)on the size effect of geopolymer recycled aggregate concrete was studied by four different size specimens(70,100,150,and 200 mm).The results show that the conversion coefficient of geopolymer recycled aggregate concrete cannot be used as specified in GB/T 50081-2002 Standard for Testing Methods for Mechanical Properties of Ordinary Concrete.In this study,two methods were used to evaluate the size conversion coef-ficient of regenerated aggregate concrete.The first method was the mean method,while the second method was linear fitting method.The compressive strength of recycled aggregate concrete of 200,150 and 100 mm are in line with the BAŽANT's theory of size effect curve,adopt the method of dimensionless can get poly-mer compressive strength of recycled aggregate concrete and sodium silicate module and size parameters of the prediction equation of coupling effect,the applicability of the proposed equation is better,and it is con-cluded that the different conditions of recycled aggregate beneath gathered the strength of recycled aggre-gate concrete critical size and critical value.