The invention discloses a growth-promoting and insect-killing slow release fertilizer and a preparation method thereof. The growth-promoting and insect-killing slow release fertilizer comprises a composition A and a composition B, wherein the composition A contains urea, calcium superphosphate, fur, feather, carbon black, polypropylene glycol, diammonium phosphate, potassium chloride, modified plant ash, bamboo charcoal, radix stemonae powder, dry silkworm excrement, gelatin, zinc sulfate, a micronutrients fertilizer, ferrous sulfate and nitrogen-fixing bacteria; and the composition B contains municipal sludge, sodium diacetate, glycerol, amino acid, calcium powder, zanthoxylum planispinum, radix euphorbiae lantu powder, ammonium molybdate, liquid paraffin and silicate potash fertilizer. The feather and the like are hydrolyzed with acid to generate the amino acid, and then secondary elements and trace elements are chelated, a chelating structure is increased due to the adoption of carboxymethylcellulose, thus invalid release of the secondary elements and the trace elements is reduced. According to the growth-promoting and insect-killing slow release fertilizer, the fertilizer efficiency utilization rate can be remarkably increased, once fertilizing and slow effective release can be realized, fertilizing frequency can be reduced, fertilizer cost is lowered, and economic benefit is increased.