NOVELTY - The method comprises mixing and heating 14.2 wt.% of monopotassium phosphate, 14.2 wt.% of urea, 17.7 wt.% of brown sugar, 30 wt.% of composite amino acid powder, 7.1 wt.% of salt, 9.1 wt.% of humic acid, 0.4 wt.% of sodium acetate, 0.2 wt.% of magnesium sulfate, 7.6% of trace element, 2.5 ml/l of molasses, and 10 ml/l of a composite liquid strain of lactic acid bacteria, Saccharomyces, actinomycetes, Aspergillus and phosphobacteria of equivalent bacteria and sterile water at 35 degrees C.    USE - The method is useful for preparing composite leaf fertilizer with bioactivity (claimed), which is useful: for promoting photosynthesis of crop, preventing disease, and resisting antibacterial and stress of the plant; and in wheat, corn, rape, rice, cotton, vegetables, and fruits. No biological data given.    ADVANTAGE - The method is capable of economically preparing the composite leaf fertilizer with high activity and quality and improved yield in an environmentally friendly manner.    DETAILED DESCRIPTION - The method comprises mixing and heating 14.2 wt.% of monopotassium phosphate, 14.2 wt.% of urea, 17.7 wt.% of brown sugar, 30 wt.% of composite amino acid powder, 7.1 wt.% of salt, 9.1 wt.% of humic acid, 0.4 wt.% of sodium acetate, 0.2 wt.% of magnesium sulfate, 7.6% of trace element, 2.5 ml/l of molasses, 10 ml/l of a composite liquid strain of lactic acid bacteria, Saccharomyces, actinomycetes, Aspergillus and phosphobacteria of equivalent bacteria and sterile water at 35 degrees C, and stirring for dissolving and chelating, placing the mixed solution into a culture tank to perform micro-oxygen thermal insulation at 28-30 degrees C, and adding photosynthetic bacteria and reacting for 48-96 hours to obtain composite leaf fertilizer with bioactivity. The composite amino acid is composed of 16-18 amino acids comprising glutamic acid, cystine, alanine, methionine, lysine, leucine, nucleic acid organic acid, and multivitamins. The total content of amino acid is not less than 55%. The organic acid is not less than 30%. The total number of viable bacteria of composite bacterium liquid of lactic acid bacteria, Saccharomyces, actinomycetes, Aspergillus, phosphobacteria and photosynthetic bacteria is not less than 0.05 million. The concentration of: ferrous sulfate is 0.001-0.015%; boron sulfate is 0.01-0.1%; zinc sulfate is 0.001-0.2%; calcium sulfate is 0.01-0.1%; copper sulfate is 0.001-0.5%; molybdenum sulfate is 0.01-0.1%; rare earth silicon is 0.01-3%; and manganese sulfate is 0.001-0.01%.