Abstract: Growth differentiation factor 9 (GDF9) gene and bone morphogenetic protein 15 (BMP15) gene were studied as candidate genes on the twinning trait in cattle Genetic variation of GDF9 and BMP15 genes in Luxi cattle, Qinchuan cattle, Nanyang cattle and Chinese Holstein cattle was analyzed. The relationship between genetic polymorphisms and twinning trait was studied in Luxi cattle The results showed that the 2-base deletion at 3′UTR of GDF9 gene was only detected in Luxi cattle. The χ2 test of association between genotypic distribution and twinning or monotocous trait in Luxi cattle showed significant difference (P=0.006). Frequency of B allele in Luxi twinning cows was higher than that in Luxi monotocous cows. According to bioinformatics analysis, the total free energy of the secondary structure of the mutation type mRNA was almost the same as the wild type mRNA But the stability of the secondary structure in translation initiation region (TIR) of mutation type mRNA was significantly higher than that of wild type mRNA.4-base deletion in coding sequence of BMP15 gene was detected in Luxi, Nanyang and Qinchuan cattle Homozygous mutation was not detected in these groups. The χ2 test of association between genotypic distribution and twinning or monotocous trait in Luxi cattle showed no significant difference (P=0.947).