The invention discloses micro-expansion concrete. The micro-expansion concrete is prepared from, by weight, 250-350 parts of sulphoaluminate cement, 500-600 parts of coarse aggregates, 250-350 parts of fine aggregates, 25-35 parts of steel fibers, 60-80 parts of water, 30-40 parts of an enhancer, 10-15 parts of a micro-expanding agent, 10-15 parts of a water reducing agent and 0-0.7 part of a retarder, and after the components are mixed and stirred, the actual density is 2,250-2,650 kg/m<3>. All the components cooperate and coordinate with one another, therefore, the micro-expansion concrete not only has the advantages of being high in tension strength and bending strength and good in impact resistance, fatigue resistance and secondary cracking resisting construction property of existing steel fiber reinforced concrete, rapid hardening concrete and polymeric rapid hardening concrete, but also has the advantages that the curing time only needs 72 hours, cost is low, preparation is easy and little pollution is generated, and then the micro-expansion concrete is more suitable for application and popularization.