Anthropology generally divides the individuals into the East Asian Mongolia race, European Caucasian race and African Nigro race. The 27-plex single nucleotide polymorphism (SNP) panel for ancestry information has been established to differentiate samples from East Asian, European, African and admixture populations of East Asian and European origin by genotyping and ancestry inference. To infer ancestry for unknown individuals, we established an optimized analysis pipeline based on the likelihood ratio, ancestry component and individual ancestry assignment. Four samples from East Asian, European, African and admixture populations of East Asian and European origin were tested using the optimized analysis pipeline. Cross validation within basic referential database and validation of 1 010 test samples were both used to evaluate the inference process. The results showed that accuracy of the method was higher than 99% in East Asia, Europe, Africa and admixture populations. The inference method can characterize the ancestry information of DNA donors, and has important practical application values in the field of human molecular and forensic genetics.