The invention discloses a collecting agent for low-grade gold ores. The collecting agent comprises, by weight, 30-34 parts of diltiazem nitrile ester, 10-12 parts of alkyl xanthate acrylonitrile ester, 10-12 parts of ammonium dibutyl dithiophosphate, 1-2 parts of sodium hydroxide, 17-19 parts of styrene phosphoric acid, 3-4 parts of 4-butanediol vinyl ether, 1-2 parts of potassium dichromate, 2-3 parts of sodium metasilicate, 2-3 parts of diphenyl ethyl phenol-compounded polyoxyethylene ether, 1-2 parts of oleic acid polyoxyethylene ester, 5-7 parts of 2-peracetic acid-group butyric acid and 10-20 parts of activator. The collecting agent has the advantages that the collecting agent can realize capturing and foaming effects, foams are stable, and the collecting agent is high in collection capacity, so that the gold ores are high in recovery rate, selectivity and grade; owing to the activator, surface hydrophobic properties of the gold ores can be changed, internal structures of the gold ores can be activated, accordingly, the gold ore collection performance of the collecting agent can be improved, characteristics of the collecting agents can be played for the low-grade gold ores, the gold ores are high in recovery rate, and gold is high in grade.