The invention discloses organic fertilizer for citrus maxima planting and a preparation method of the organic fertilizer and belongs to the technical field of organic fertilizer. The organic fertilizer is prepared from raw materials in parts by weight as follows: 10-30 parts of ammonium molybdate, 10-20 parts of urea, 5-15 parts of potassium sulfate, 5-15 parts of cushaw stem, 4-10 parts of diammonium phosphate, 6-16 parts of thiourea, 6-16 parts of diatomite and 10-20 parts of a traditional Chinese medicine preparation, wherein the traditional Chinese medicine preparation is prepared from rawmaterials in parts by weight as follows: 10-20 parts of semen euryales, 5-15 parts of cortex meliae, 4-10 parts of radix astragali, 6-12 parts of caulis polygoni multiflori, 5-15 parts of herba agrimoniae, 4-10 parts of cyrtomium rhizome, 6-10 parts of herba artemisiae scopariae, 5-15 parts of radix bupleuri, 10-20 parts of perilla stem, 5-15 parts of fructus quisqualis and 6-16 parts of radix puerariae. According to the organic fertilizer, not only can the requirement for a large quantity of nutrient elements for citrus maxima growth be met, but also the yield of citrus maxima can be increased, and the incidence rate of pest and disease damage can be remarkably reduced.