The application relates to an environmentally friendly lightweight concrete of waste fired bricks and tiles and a preparation method thereof, which belongs to the technical field of concrete. The raw materials of lightweight concrete include cement, water, waste fired bricks and tiles, fly ash, slag, silica fume, polymer Acrylonitrile fiber, plastic steel fiber, polystyrene particles, ceramic powder, silica powder, polycarboxylate high-efficiency water reducer, phenolic resin, and through the synergistic effect between raw materials, under the condition of ensuring low thermal conductivity of lightweight concrete , so that the lightweight concrete has good compressive strength and flexural strength, and also makes the lightweight concrete have good frost resistance. In the preparation method of environmentally friendly lightweight concrete, the waste sintered bricks and tiles are pre-mixed with soaking water, and the fly ash and adsorption water are pre-mixed to reduce the mixing effect of waste sintered bricks, tiles and fly ash due to the adsorption of water. , so that the mixing of raw materials is uniform and stable.