The invention discloses an animal nutrient additive trace element compound bag as well as a preparation method and an application thereof. The compound bag mainly comprises compound glycine polymineral, selenite and basic salt of a trace element, wherein the compound glycine polymineral contains copper glycinate, ferrous glycinate, zinc glycinate, manganese glycinate and the like; and the basic salt of the trace element contains at least one of basic chlorate, basic carbonate and basic sulfate corresponding to the trace elements such as copper, zinc, and manganese. The preparation method comprises the following steps of: mixing the glycine raw material and the inorganic trace element compound, adding the mixture into water, regulating the pH value, heating, fully stirring, reacting, then discharging, adding other raw materials into the reaction product to form uniformly dispersed suspension, drying, granulating, and thus obtaining the trace element compound bag. The trace element compound bag can be used as an animal feed additive, and has the advantages of simplified process, high biological value, low adding quantity, obvious growth-promoting effect, low side reaction of animals and the like.