Supersulfate cement is a kind of resource saving and environmentally friendly cementitious material, but its application is limited because of its low strength in early stage. In order to improve its early strength, the effect of sodium lactate content on the strength of supersulfate cement was studied, the ion concentration, hydration products and microstructure were analyzed by ICP-OES, MIP, XRD and SEM, and the related mechanism was discussed. The results show that the strength of supersulfate cement, especially the early strength， is improved by adding a small amount of sodium lactate, but it is detrimental to the strength when adding too much. Considering the increasing effect of early strength and late strength, the suitable content of sodium lactate is about 0.25% (mass fraction). The main reason why sodium lactate improves the strength of supersulfate cement is that sodium lactate can promote the dissolution of slag, accelerate the formation of ettringite and C-S-H, and thus improve the microstructure of cement.