The invention provides an application of 2-ethyl-2-hexenealdoxime serving as a new collecting agent in mineral flotation. The collecting agent has a high collecting capacity for copper sulfide ore, copper sulfide-copper oxide ore, tungsten ore and tin ore; the appropriate flotation pulp pH ranges from 8 to 13; when the collecting agent is used as a sulfide ore flotation collecting agent, the dosage ranges from 30g/t to 200g/t; and when the collecting agent is used as an oxidized ore flotation collecting agent, the dosage ranges from 200g/t to 1,500g/t. By virtue of good hydrophobic group structure and collecting selectivity, 2-ethyl-2-hexenealdoxime has strong collecting acting force and good hydrophobic floating capacity for targeted ore, and is suitable for treating fine grained ore which is difficult to select; and when the copper sulfide-copper oxide ore is in flotation, the flotation can be performed without adding a sulfurizing reagent such as sodium sulfide and the like.