The invention discloses a barium residue coal ash building block and a productbulion method thereof. The barium residue coal ash building block is made in the manner that barium residue, coal ash, cement, water and an additive that is used for eliminating the toxicity of barium residue are taken as raw materials, and the raw materials are processed through metering, stirring and blending, compression moulding and stacking and maintaining; and the additive adopts soluble sulfate and slightly soluble sulfate. Desulfurized gypsum is used as the additive used for eliminating the toxicity of barium residue, and the raw material formula of the barium residue coal ash building block includes, by the mass proportion, 50 cement, 450 mountain sand, 400 barium residue, 100 coal ash, 50 desulfurized gypsum and appropriate amount of water; and sodium sulfate is used as the additive for eliminating the toxicity of barium residue, and the raw material formula of the barium residue coal ash building block includes, by the mass proportion, 50 cement, 500 mountain sand, 400 barium residue, 100 coal ash, 6 sodium sulfate and appropriate amount of water. According to the invention, the pollution to the environment from barium residue is reduced; clay bricks are replaced with waste materials to achieve waste material utilization, which meets the requirement of developing recycling economy; and the building block cost is lowered. The invention is suitable for building material producing enterprises discharging barium residue.