Somatic cells contain individuals with complete genomes. In nature, somatic cells of most species contain two kinds of complete staining ... Now haploid plants have been obtained from nearly 100 plants by pollen culture, and then doubled into homozygous diploids, including food crops, cash crops, ornamental plants and woody plants. The offspring of excellent homozygous lines selected from them are not separated, and their performances are neat and consistent, which can shorten the breeding cycle. Because plants are highly sterile and weak, they cannot be directly used, but haploid breeding is a shortcut to create and cultivate homozygous diploid or polyploid plants. Homozygous diploids can detoxify and maintain excellent genes. Haploid plants can appear homozygous diploids in the first generation after chromosome doubling, and the offspring of excellent homozygous lines selected from them are not separated, and their performances are neat and consistent, which can shorten the breeding cycle. Traits controlled by recessive genes in haploid plants are easy to appear because they are not covered by dominant genes, although they are doubled in chromosomes. This is very beneficial to mutation breeding and mutation genetic research. When the frequency of induction is high, haploid can fully reveal the types of recombinant gametes in plants and provide new genetic resources and selection materials. China first used haploid breeding to improve crop varieties, and has cultivated some excellent varieties, such as tobacco, rice and wheat. Haploid breeding will play a greater role in crop variety improvement if it can further improve the induction frequency and combine with cross breeding, mutation breeding and distant hybridization.