Abstract: A method for rapidly identifying porcine estrogen receptor (ESR) marker comprises using published primers to amplify the target DNA fragment by polymerase chain reaction (PCR). The DNA fragment is cloned and then sequenced. The key positions of the sequence are modified to generate three primers which are used to amplify different DNA fragments with different genotypes by PCR to eliminate extra restriction cut reaction. A long one of the primers is to specifically amplify non-prolific allele, a short one of the primers is to specifically amplify prolific allele, and the remaining one is mutual and complimentary to the sequence. After PCR and electrophoresis, the sample with 90 bp band is identified as prolific genotype, the sample with 110 bp band is identified as non-prolific genotype, and the sample with 90 bp and 110 bp bands is identified as hetero-genotype.