Seventy samples randomly selected from Hunan Han nationality normal individuals were typed for HLA DPA1 polymorphism by PCR/SSO with the primers and SSOs. Silver staining PCR/SSCP was also performed on the polymorphic second exon of all samples, which demonstrated the accurate gene frequencies of DPA1*01,02 to be 0.2632 and 0.7327, respectively. Using PCR/SSCP technique, we found that PCR/SSO mistyped a DPA1*01/02 heterozygote as single DPA1*01 gene because of weak hybridization signals. PCR/SSCP also revealed DPA1*02 in Hunan Han population to be composed of a single subtype. The results indicate that PCR/SSCP can be used to clarify the samples with atypical or irregular PCR/SSO hybridization patterns and to analyze the possible polymorphisms outside SSOs sequences. Thus this method may guarantee the accuracy of HLA oligotyping.