his paper introduces M and KM agents used in cement concrete successfully asearly strength agents.They are used in lime-sand concrete in the laboratory.Through the experi-ments,it is verified that both agents can increase the strength of lime-sand concrete on weaker auto-claving conditions and KMagent is better than M agent.Under the condition of this experiment,theoptimum proportion of the agents in lime-sand concrete and the optimum autoclaving schedules areexplored and the effects of saving energy of the two kinds of agents are estimated.