The invention discloses a coagulation time control agent with the effect of accurately adjusting Portland cement clinker coagulation time. The coagulation time control agent comprises, by mass, 15-40% of calcium carbonate, 20-35% of sodium carbonate, 20-35% of sodium bicarbonate, 5-25% of silica aerogel, 1-10% of copper oxide and 1-10% of zinc oxide. One or more of calcium carbonate, sodium carbonate, sodium bicarbonate, silica aerogel, zinc oxide and copper oxide are used as coagulation time control agent components of a cement clinker so that the coagulation time control agent can accurately adjust Portland cement clinker coagulation time, and an obvious time interval between initial setting and final setting is avoided, in other words, initial setting and final setting are not carried out individually and the Portland cement clinker only be subjected to a setting process as the final setting process. The coagulation time control agent can be used for military first-aid repair fortification, fast molding of concrete and concrete fortification building with accurate coagulation time requirements.