The invention discloses a low-mercury catalyst and particularly relates to the low-mercury catalyst which is suitable for synthesizing vinyl chloride by hydrochlorination reaction of acetylene. The catalyst comprises a main active component, namely mercury chloride, auxiliary active components, namely at least one of oxides of cobalt, manganese, silver and copper and a carrier, namely activated carbon, wherein the mercury chloride accounts for 2-4% of the weight of the carrier of the catalyst, and the auxiliary active components account for 5-30% of the weight of the carrier of the catalyst in total. According to the prepared low-mercury complex catalyst disclosed by the invention, the auxiliary components are added, so that the anti-poisoning performance of the low-mercury catalyst is enhanced, the reduction of the mercury chloride during the using process is reduced, the loss of mercury is retarded, the service life of the low-mercury catalyst is significantly prolonged, and the low-mercury catalyst is the novel low-mercury catalyst with good activity, strong stability and high selectivity. The low-mercury catalyst has the advantages of simple production process, short production period and low mercury consumption.