Abstract: The arsenic acid mud was researched which came from the process of producing sulfuric acid with smelting gas in this article. The results showed that acid mud can be solidified with chemical additive A ,FMH and KZF. In the conditions of simulated poor nature ,the concentration of arsenic of solidified body is 0.026 mg/L,and it is lower than 0.5 mg/L of the national emission standard. The SEM showed that the internal structure of solidified body is fine after test. The solidified body is made of Al-O-Al-As-,-Si-O-Si-As- and -Al-O-Si-As- through XRD analysis. The chemical structure belongs to the class ceramic, and has chemical stability and high strength characteristics.