In order to recycle soda residue, a kind of binding material from it to mix with slag was developed. Meanwhile, microstructures and compositions of hardened paste of soda residue slag complex binding materials(SSCBM) after curing for 28days were analyzed by means of scanning electron microscope, energy dispersive X ray spectroscopy, X ray diffraction and thermogravimetric differential scanning calorimetry. The results show that when water binder ratio is 05 and sand binder ratio is 3∶1, soda residue and slag are prepared according to the mass percentage of 1∶4, the compressive strength of the SSCBM specimen(40mm×40mm×160mm) is 396MPa, the flexural strength is 80MPa, and the chemical binding rate of chloride ions is 844%. A large number of hydration products between 510μm are observed in the SSCBM system; meanwhile, the hydration products are bonded to each other to form a dense three dimensional network structure. The hydration products of binding materials after curing for 28days are mainly C S H gel, C A C H gel, C A S H gel and 3CaO·Al2O3·CaCl2·10H2O crystal(Friedels salt).