Active carbon (AC)-supported AuCl3 catalysts are considered the most promising materials for acetylene hydrochlorination. However, there is no consensus on the reaction mechanism. In this paper, the mechanism and reaction steps of Au(I)-catalyzed acetylene hydrochlorination have been investigated by theoretical calculations. The results show that C2H2 assists in the electrophilic addition of HCl, facilitating a change between the Au(I) and Au(III) redox couple. The linear structure of AuCl is proposed to form a tetracoordinated five-membered ring transition state, which is accompanied by the oxidation of Au from Au(I) to Au(III). Besides, we explored and compared the reactivity and energy difference between Au(III)- and Au(I)-catalyzed acetylene hydrochlorination. The DFT calculations indicate that a strong combination between the Au center and ligands and the favorable hydrogen-transfer angle (close to 180°) significantly enhance the activity of the AuCl3/AC catalyst. We also investigated the change from AuCl3 to AuCl, which suggests that the process of decomposition of AuCl3 to AuCl is highly possible. These understandings and explanations also open up an intriguing route to design a novel ligand, which is promising to maximize catalytic performance in acetylene hydrochlorination by increasing the stability of Au(III) in the catalytic cycle.N-doped carbon material is a promising alternative to mercury catalyst for acetylene hydrochlorination. Herein, we present an innovative strategy to synthesize pyridinic N-rich aromatic ladder structure material through controlling the self-assembly of polyacrylonitrile polymer chains. The prepared material gave ∼93% conversion of acetylene with >99% selectivity for vinyl chloride and exhibited a satisfying stability during 200 h lifetime test. Characterizations and density functional theory calculations demonstrated that the activity of the catalyst likely originates from three types of active pyridinic N sites in the ladder structure. Particularly, the pyridinic N sites with one H atom nearby are more active because the H atom can stabilize the transition state through H···Cl bond, thereby reducing the energy barrier. The energy barriers on these pyridinic N sites were calculated to be 29.8 and 47.4 kcal mol–1, much lower than 83.2 and 84.4 kcal mol–1 on those sites without H atom nearby. The facile and highly effective strategy for the synthesis of a specific N species with defined formation mechanism is expected to be helpful in the design of other green catalysts for acetylene hydrochlorination.