Portland cement-calcium sulphoaluminate cement-flue gas desulfurization gypsum ternary binder （PC-CSC- FDG ternary binder）was used to prepare repair mortars， and the effects of tartaric acid， borax， sodium hexametaphosphate and their mixtures on the properties of the repair mortar were investigated. The results show that tartaric acid has no retardation effect， and can significantly reduce the fluidity， mechanical properties and drying shrinkage of the repair mortar. Borax and sodium hexametaphosphate can significantly prolong the setting time and improve the fluidity of repair mortar. Borax has negligible influence on the flexural strength， but can significantly increase the compressive strength and the drying shrinkage. Sodium hexametaphosphate can slightly reduce the early strength， but improve the strength at the middle and late ages， and significantly reduce the drying shrinkage. All these three retarders yield decrease of tensile bond strength to some extent. The effects of retarder double-mixture on properties are the effect superpositions of the corresponding retarders.