The invention relates to a floating and collecting agent of bertrandite beryllium ores and application thereof. In the invention, benzohydroxamic acid is used as an organic compound collecting agent, and after benzyl is introduced to hydroximic acid, the selective collecting capacity to beryllium ores of hydroximic acid medicaments is improved. The floating and collecting agent is used for the flotation of the bertrandite beryllium ores, has excellent selective collecting property and is a high-efficiency floating and collecting agent for the beryllium ores.