The invention provides an application method of an ester-based hydroximic acid collecting agent to mineral flotation, and belongs to the technical field of mineral flotation. The structure of the ester-based hydroximic acid collecting agent is shown in the formula I shown in the specification, wherein in the formula I, R is a C1-C17 alkane base or C2-C17 alkylene. Due to the fact that the molecule of the ester-based hydroximic acid collecting agent contains an ester base and a hydroximic acid base, more ligating atoms and more coordinating groups are obtained, through chelation and metal ions, the more stable complex compound can be formed or strong adsorption is formed on the surfaces of metal oxide minerals, and floatation recycling of rare earth ores, titanic iron ores, scheelite, wolframite, scheelite and wolframite mixture ores or tin ores ca be strengthened; compared with an existing hydroximic acid collecting agent, due to the fact that the ester base exists in the molecule, the beneficial effects of being good in biodegradability, small in poisonousness and friendly to the environment are achieved.