The invention discloses a collecting agent for bauxite floatation and a preparation method of the collecting agent. The collecting agent for bauxite floatation is prepared from the raw materials comprising aliphatic acid, aliphatic amine, naphthenic acid, dimethicone, emulsifier, caustic soda and water, wherein the weight ratio of the aliphatic acid to the aliphatic amine to the naphthenic acid to the dimethicone to the emulsifier to the caustic soda and to the water is 50:10-15:10:3:10-15:10:25. According to the collecting agent for bauxite floatation and the preparation method of the collecting agent, the emulsifier and the caustic soda are added stepwise, and the emulsification function and the saponification function on the aliphatic acid are achieved; and in this way, the defect that after saponification, conventional aliphatic acid is poor in mobility is relieved, the HLB number is improved, and meanwhile the good mobility of the aliphatic acid can be maintained. The collecting agent for bauxite floatation can be directly added in the bauxite floatation process or is prepared into a milky solution at the normal temperature to be used. Compared with a conventional collecting agent, the obtained collecting agent for bauxite floatation has the beneficial effects of being good in water solubility, resistant to low temperature, low in dosage, easy to defoam, good in selectivity and collecting capacity and the like.