The invention discloses an environment-friendly polyaluminum chloride water purifying agent, which comprises the following components by weight: 30-42 parts of polyaluminum chloride, 9-15 parts of activated carbon, 13-20 parts of aluminum sulfate, 6-9 parts of ferric chloride, 8-11 parts of ferric sulfate, 4-7 parts of bentonite, 15-18 parts of a shell filter material, 1-3 parts of paracoccus aminovorans powder, and 0.9-1.5 parts of nitrobacteria powder. The purified water quality is superior to that purified by an aluminum sulfate flocculant, and the water purification cost is about 20% lowerthan that adopting aluminum sulfate flocculant; the consumption of alkalinity in the water is lower than that of various inorganic flocculants, therefore no or a small amount of alkaline agent can beapplied. And the polyaluminum chloride water purifying agent has a wide PH application range. Only two main raw materials are used in production, the raw material variety is simplified, the technological process is shortened, and the reaction is accelerated. The product is clear, the quality and performance are improved, the basicity is increased by about 10% than that of products adopting aluminum hydroxide as the raw material, and the production cost is reduced by 20% or more, and compared with products adopting bauxite as the raw material, the waste residue is reduced by 20-30%, thus beingconducive to environmental control.