The invention relates to recycled concrete and a preparation method thereof, wherein the recycled concrete comprises, by weight, 60-70 parts of recycled coarse aggregate, 18-22 parts of natural coarseaggregate, 15-20 parts of slag Portland cement, 15-20 parts of fine sand, 10-15 parts of activated water, 8-12 parts of fly ash, 5-8 parts of modified polypropylene fiber, 4-6 parts of a binder, 3-5parts of silica powder, 3-5 parts of manganese dioxide powder, and 3-5 parts of a water reducing agent. The preparation method comprises: S1, breaking waste concrete to form recycled coarse aggregate;S2, screening the recycled coarse aggregate with a particle size of 10-15 mm so as to be spare; S3, cleaning the surface of the recycled coarse aggregate to remove the residual cement mortar on the surface; S4, mixing, wherein the raw materials are sequentially mixed, and uniform stirring is performed to obtain a recycled concrete slurry; and S5, pouring with the recycled concrete slurry, vibrating, and molding. According to the present invention, the recycled concrete has the improved strength.