The invention discloses a method for manufacturing a concrete building material from construction waste. The method comprises the following steps that: collected waste bricks, waste concrete blocks and other construction waste are all shoveled to a roller conveying mechanism through a forklift, then the construction waste is conveyed to one side through rollers rotating in the same direction, small broken stones can fall down from gaps among the rollers in the conveying process, and large construction waste is still conveyed to the side; and barriers are arranged at large intervals at positions where small gravels hardly exist in a rear half section, so plastic bags and the like in the passing construction waste are intercepted. The invention relates to the technical field of constructionmaterials. According to the method for manufacturing the concrete building material from the construction waste, waste steel bars in the construction waste are processed and manufactured into wavy orspiral steel bar sections, and the wavy or spiral steel bar sections are used as a framework of the building material for filling, so the processed building material is higher in strength and strongerin bearing capacity; and compared with conventional building materials, the comprehensive performance of the building material is greatly improved, waste is utilized, and the building material is environmentally friendlier.