The invention belongs to the technical field of molecular marker screening of livestock and particularly relates to a genetic marker associated with the lactation traits of mediterranean buffalo. Themarker is screened from an ACAAI gene of the buffalo, the sequence of the marker is shown in SEQ ID NO: 1, A/T base mutation occurs at the 776th site of base of the sequence, and then the polymorphismof the ACAA1 gene is caused. A screening method comprises the following steps: extracting genome DNA from the blood of the buffalo, designing a primer, carrying out PCR amplification, carrying out cloning on the PCR product, carrying out sequencing, carrying out comparative analysis on the sequence, carrying out SNP detection, carrying out mass spectrum typing, carrying out labeling, and carryingout correlation analysis among the lactation traits. The invention discloses an SNP typing detection technology for a promoter region of the ACAA1 gene of the mediterranean buffalo, and the result shows that the A/T mutation site is obviously associated with the lactation traits including the 305d milk fat yield, the 306d milk protein yield, the 305 butter-fat percentage, the 305 milk protein yield, and the like. With the technical scheme, a novel genetic marker resource is provided for the marker assisted selection of buffalo.