Abstract: Objective: To develop HLA B27 typing by a group specific polymerase chain reaction（PCR） amplification with a sequence specific primer pair（PCR SSP）. Methods: A new and simple DNA extraction method from 200μl peripheral blood sample was used and a HLA B27 sequence specific primer pair for exon 2 of the HLA B27 gene based HLA class I antigen sequence were designed Two hundred and twenty five DNA samples from patients with spondyloarthropathies（SpAs） and other arthritis were amplified by PCR with B27 SSP All samples were also tested by Microlymphocytotoxicity test（MLCT）. Results: 174 （77 3%） HLA B27 positive samples were found by PCR, 153 （68 8%） by MLCT with a coincident rate of 83 9% In 88 inpatients with definite SpAs, the HLA B27 positive rate was 92 1% by PCR and 81 8% by MLCT, and the coincident rate was 89 8% The positive rate of PCR method was 10 3% higher than that of MLCT DNA extraction and PCR amplifying could be finished within 6 hours. Conclusion: PCR is superior to the MLCT to determine HLA B27 The method we described is sensitive, specific, simple and rapid, particularly when large numbers of samples are being studied.