Pi2 is a rice gene for broad-spectrum resistance to blast pathogens, which has an important application value for rice blast resistance breeding in South China. In order to improve the selection efficiency, a KASP marker specific for Pi2 gene was developed based on the variation GCA GGA / GTG TTA at codon 787 and 788 of Pi2 gene between the highly resistant variety Huangguang Youzhan and the highly susceptible variety Guanglu Ai 4. The developed allele specific marker could accurately distinguish the resistance allele, susceptible allele and heterozygous genotype at Pi2 in 40 rice varieties, which was highly correlated with their resistance/susceptible phenotypes. Further more, this marker was applied in a large F2 segregation population from a cross of Wushan Youzhan and Yujing 91 to select the target genotypes of the individuals or lines that carried the blast resistance Pi2 alleles through marker-assisted selection exhibited intermediate or high resistance to blast in disease nursery. In conclusion, using the developed allele specific marker, 27 Guangdong rice varieties that carry blast resistance gene Pi2 were identified, which has an important application value in improving selection efficiency in the development of blast resistant rice varieties.