Abstract: Bovine leukocyte adhesion deficiency （BLAD） is an autosomal recessive disease caused by A→G mutation in the CD18 gene. The disease is characterized by greatly reduced expression of the heterodimeric β2 integrin adhesion molecules on leukocytes， resulting in multiple defects in leukocyte function and significant deficits on performance traits in Holstein cattle. In this study， primers were designed to amplify the exon2 fragment of CD18 gene and BLAD was detected by PCRSSCP. There were four different haplotypes which were H1， H2， H3， and H4， respectively. Two SNPs were confirmed in the amplification fragment by DNA sequencing. C20T mutation of the exon2 is silent mutation which is novel and A55G is missense mutation which induces BLAD. Haplotype H1， H2， H3 are normal while haplotype H4 is BLAD carrier. Our aim is the identification of BLAD carriers， and therefore this study provides a more reliable and useful method for extensive screening of BLAD.