Based on quantitative analysis of adhesion mortar on recycled coarse aggregate and literature data, the relationship between its content change and physical properties of recycled coarse aggregate were studied. The rule of mechanical properties of concrete with 100% recycled coarse aggregate and different adhesion mortar content was determined. Taking the adhesion mortar content as independent variable, the mechanical properties as dependent variable and the target strength as the limit value, the limit content was determined by mathematical method. It is found that the physical properties of recycled coarse aggregate decreases with the increase of adhesion mortar content. The compressive strength, splitting tensile strength and elastic modulus of recycled coarse aggregate concrete decrease with the increase of adhesion mortar content. The effect of adhesion mortar content on splitting tensile strength is greater than that of compressive strength. The elastic modulus fluctuates greatly under the influence of mortar content. After numerical fitting, the relationships between compressive strength, splitting tensile strength and adhesion mortar content are quadratic. The relationship between elastic modulus and adhesion mortar content are accorded with Boltzmann formula. Based on the fitting results, it is determined that the limit contents of adhesion mortar satisfying compressive strength, splitting tensile strength and elastic modulus of C40 recycled coarse aggregate concrete are 45%, 43% and 39% respectively.