The invention relates to recycled concrete and a preparation method thereof, and belongs to the technical field of concrete. The recycled concrete comprises (by weight): 150-280 parts of cement, 90-130 parts of water, 800-950 parts of modified recycled coarse aggregate, 400-530 parts of fine aggregate, 40-85 parts of fly ash, 80-100 parts of mineral powder, 50-140 parts of zeolite powder, 30-60 parts of epoxy resin, 4-10 parts of a water reducing agent and 2-6 parts of an air entraining agent. The preparation method of the modified recycled coarse aggregate comprises the following steps: S1, crushing and screening waste concrete to obtain recycled coarse aggregate; S2, soaking the recycled coarse aggregate obtained in the step S1 in an acetic acid solution with the mass concentration of 2-7%, and airing; S3, stirring 80-110 parts of polyvinyl alcohol, 60-110 parts of silica fume, 40-80 parts of sodium silicate and 800-1,000 parts of water to obtain a modified liquid; and S4, soaking the recycled coarse aggregate obtained in the step S2 in the modified liquid obtained in the step S3, taking out the soaked recycled coarse aggregate, and baking the recycled coarse aggregate to obtainthe modified recycled coarse aggregate. The recycled concrete provided by the invention has a good compressive strength effect.