Abstract: The trait of nipple is one of the important factors to evaluate the breeding ability of pig. Eralvation of pig reproductive capacity by nipple traits plays an important role in improving the production level and promoting the economic benefits of pig farms. In order to explore the main factors affecting the traits of pig nipple and improve the reproductive performance of pigs, the pig nipple traits were summarized from the number, shape and distribution of pig nipples, the development of breast and nipple, and the heritability of pig nipple traits in this article. And the factors affecting pig nipple traits were summarized from the perspectives of pig breeds, inbreeding and crosses, hormones, and genes related to pig nipple traits. The ideas for improving sow traits, improving their reproductive performance, and breeding sow breeds and strains with excellent economic characteristics were provided by studying these influencing factors.