The invention discloses a preparation method of rice fertilizer and relates to the technical field of agriculture. The rice fertilizer is prepared by, by weight, 20-35 parts of mixed phosphorus fertilizer, 30-60 parts of urea, 5-10 parts of ammonium sulfate, 20-60 parts of potassium sulfate, 12-16 parts of calcium nitrate, 8-12 parts of magnesium sulfate, 2-5 parts of ethylene diamine tetraacetic acid iron, 2-4 parts of sweet potato leaf, 4-5 parts of bamboo shoot shell, 6-8 parts of carboxymethyl chitosan, 3-4 parts of lignocellulose, 2-4 parts of processed monkshood, 3-4 parts of radix rehmanniae preparata, 4-6 parts of tea polyphenols, 1-3 parts of lignosulfonic acid, 2-4 parts of zinc gluconate, 3-4 parts of organic acid, 1-2 parts of zinc sulfate and 4-6 parts of nitrogen-fixing bacteria. The preparation method has the advantages that the method is low in raw material cost, and the prepared rice fertilizer is high in quality, high in content, high in utilization rate, pure natural, green, good in economic benefit, capable of increasing rice yield, capable of satisfying the needs of massive farmers and promising in development aspect.