The invention relates to a molecular genetic marker associated with egg-laying traits of ducks and application of the molecular genetic marker, belongs to the field of poultry breeding, and particularly relates to application of a G575A site of an AMH (anti-Mullerian hormone) gene, associated with egg-laying traits of ducks, serving as a molecular genetic marker in duck production performance research. A specific DNA segment is obtained from the AMH gene to serve as a molecular marker associated with the egg-laying traits of the ducks, one G575-A575 basic group in a sequence of the molecular marker mutates, the mutation site is significantly associated with the 43-week-old egg production and the 72-week-old egg production of the ducks (P smaller than 0.05), and by performing PCR (polymerase chain reaction) amplification and performing sequencing-based typing on a PCR product, a GG genotype is selected as an laying duck. A detection method provided by the invention is significant in effect, is simple and quick, and is not influenced by an external environment.