Five quaternary ammonium ionic liquids (QAILs) were employed to synthesize Ru-based catalysts with the purpose of exploring an efficient non-mercuric catalyst for the acetylene hydrochlorination reaction. The activity and stability of Ru-QAILs/AC catalysts were investigated. Importantly, the method and sequence of impregnation were compared. The 0.1Ru15TBAH/AC catalyst prepared by co-impregnation method achieved 95% initial conversion of acetylene and 99.5% selectivity of vinyl chloride, and remained stable in the 200 h life evaluation under the conditions of T = 170 degrees C, GHSV(C2H2)= 90 h(-1) and V(HCl): V(C2H2)= 1.1. A series of characterizations demonstrated that the addition of TBAH could improve the dispersion of Ru species, effectively prevent the appearance of coke deposition and increase the content of Ru4+ active species. Particularly, the mechanism of coke inhibition by adding TBAH IL was discussed via Temperature-programmed desorption (TPD) analysis, and the interaction mechanism of TBAH IL with the AC support and with the Ru species were revealed via XPS spectrum combined with density functional theory (DFT) calculations.