The wide range of chemical modifying admixtures is used in gypsum-cement-puzzolan binders production. Complex chemical admixtures with multi-functionality of the effect have more powerful capabilities in controlling setting process of binders based on gypsum and portland cement. In this regard, production of the polyfunctional complex admixtures with the purpose of improving the performance properties of gypsum-cement-puzzolan compositions is a relevant objective and necessitates undertaking experimental studies. This work objective consists in studying characteristics of interreaction of chemical modifiers in structure and gypsum-cement-puzzolan binders’ properties, in determining their mechanism of synergistic interaction, in production and optimization polyfunctional complex admixture (CA) composition that helps to improve performance properties of gypsum-cement-puzzolan stone based on low-graded gypsum binder. In consequence of undertaken studies the mechanism of synergistic interaction of superplasticizing admix “Best-TB”, polycarboxylate superplasticizer “Odolit-K”, organosilicone compound “N-oktiltriehtoksisilan” was determined. With the use of these chemical modifiers the polyfunctional complex admixture that helps to improve the performance properties of gypsum-cement-puzzolan compositions was produced. Based on mathematical experimental design techniques optimum doses of above-named chemical admixtures in composition of mixture were determined. Elaborated polyfunctional complex  admixture with tailored composition helps to raise coefficient of softening of the products based on studying type of binder to 0.98, ultimate bending strength – by 86%, frost resistance – by a factor of 4.2