Engineering cementitious composites(ECC)have good ductility and tensile properties. However, the molding shrinkage rate of ECC is large, which leads to cracking in the molding process of specimens and seriously affects the durability of structure. High performance calcium sulpho aluminate(HCSA)expansion agents were added into ECC to reduce the molding shrinkage rate, and the influences of different expansion agents content on the molding shrinkage rate and mechanical properties of ECC were investigated. The results show that the shrinkage rate of ECC can be improved significantly when expansion agents content is 6%~8% (mass fraction same below), but excessive expansion agents will cause expansion of ECC. The compressive strength of ECC significantly increases and there is little change in the tensile strength when expansion agents content is 4%~6%. The shear toughness of ECC significantly increases and there is little change in the shear strength when expansion agents content is 2%~4%. The maximal flexural strength of ECC significantly increases when expansion agents content is 6%~8%.