Abstract: PCR-RFLPs assay was used to investigate polymorphisms within the cloned introns 5 to 7. A MspI-RFLPs and a TaqI-RFLPs were detected in intron 6.The MspI-RFLPs is common in all the detected breeds, but the TaqI-RFLPs only was founded in Chinese breeds, and allele B(bearing T base) is rare in Chinese breeds. Associations between the founded MspI-RFLPs in intron 6 and carcass traits in the seven beef cattle breeds and two Chinese dairy cattle were tested , no relation between MspI-RFLPs and body fat in beef cattle were founded in present study, but the individuals bearing AA genotype had higher(P<0.05)dressing percentage. Individuals with genotype AA had higher milk fat percentage（P<0.01）and dry material percentage（P<0.05）in Sanhe .For the TaqI-RFLPs in intron 6, the present study only tested the carcass trait's difference between genotype AA and AB in Luxi cattle, but no associations were founded.