The present invention mainly relates to formation of zebrafish with hepcidin gene knocked out, by the use of CRISPR / Cas9 technology, a unique PAM region is designed, so that the hepcidin gene in the zebrafish is knocked out, and other genes are not accidentally injured. The first case of hepcidin knockout transgenic animal model zebrafish has great significance, the hepcidin is a major factor in the regulation of iron, once the hepcidin is knocked out, an animal model can be successfully molded into an iron overload animal model, the human factor intervention can be excluded, the hepcidin has great significance to iron expression researches, meanwhile compared with the traditional gene knockout technology, the CRISPR / Cas9 technology has low toxicity, high accuracy, high efficiency, short success cycle and other characteristics, and the hepcidin gene can be faster knocked out.