Abstract: Pyrolysis char was prepared from high sulfur and iron content textile dyeing sludge. The combined states of S and Fe in the samples before and after pyrolysis and the removal characteristics of Hg⁰ by pyrolysis char were studied. The performance of Hg⁰ removal was improved by air oxidation and ZnCl₂ impregnation. The results showed that S in sludge was divided into sulfate, sulfide, and organic sulfur. Fe existed as Fe³⁺ and Fe²⁺ compounds. After pyrolysis, inorganic sulfur was transferred to organic sulfur and Fe³⁺ was transferred to Fe²⁺. Most S and Fe were retained in pyrolysis char and some formed pyrrhotite (Fe_1−xS). The specific surface area of raw char was small and had a certain Hg⁰ removal capacity, dominated by chemical adsorption. When the air oxidation time was controlled within 12 h, the Hg⁰ adsorption capacity of pyrolysis char at high temperature (≥600 ℃) was increased by more than 46%. During pyrolysis of ZnCl₂ impregnated sludge, more S was fixed in pyrolysis char to generate ZnS. The Hg⁰ adsorption capacity of ZnCl₂ modified char pyrolyzed at 600 ℃ reached 28.71 μg/g in 30 min. With air oxidation, the Hg⁰ removal efficiency was further improved. After oxidation for 12 h, the Hg⁰ adsorption capacity was 43.75 μg/g.