NOVELTY - Preparing ammonia copper citrate, comprises (i) uniformly dispersing water and copper sulfate powder; (ii) adding copper sulfate solution with sodium citrate, and stirring; (iii) heating to boil step (ii) product, precipitating, and filtering; (iv) adding precipitate into a reaction kettle, adding water, and stirring; (v) adding aqueous ammonia into the reaction kettle, and stirring while reacting; (vi) heating to boil the step (iv) product, concentrating; (vii) cooling the concentrated liquid to room temperature by adding remaining amount of aqueous ammonia, stirring, drying, and crushing.    USE - The ammonia copper citrate is useful as plant trace elements regulators (claimed).    ADVANTAGE - The method is environmental friendly; does not produce residues; utilizes raw materials having good compatibility, nutrient absorption property, and low cost raw materials; and is suitable in agricultural development.    DETAILED DESCRIPTION - Preparing ammonia copper citrate, comprises (i) uniformly dispersing water and copper sulfate powder in a stirring device, to obtain copper sulfate solution; (ii) adding copper sulfate solution with sodium citrate, and continuing stirring process until the solution color changes into transparent solution; (iii) heating to boil the step (ii) product, precipitating, and filtering the precipitate; (iv) adding the precipitate into a reaction kettle, adding water, and stirring to disperse uniformly; (v) adding aqueous ammonia into the reaction kettle, and stirring while reacting, until there is no presence of precipitate; (vi) heating to boil the step (iv) product, and concentrating the material to 1/2 the volume; (vii) cooling the concentrated liquid to room temperature by adding remaining amount of aqueous ammonia, stirring while reacting, adding into a baking box, and drying moisture content, to obtain a solid material, cooling, and crushing, to obtain the finished product, where the raw materials include 100 pts. wt. water, 12.5-13.5 pts. wt. sodium citrate, 16-17 pts. wt. copper sulfate powder and 20-30 pts. wt. aqueous ammonia.