Abstract: Analying the seven major amino acids’ content under different radiation doses in Pleurotus geesteranus. Applying multivariate statistical component analysis, the related and principal component analysis was finished. The results showed that there was an extremely obvious positive correlation between the content of tasty amino acids and branched chain amino acid as well as the content of aromatic amino acid and essential amino acid, the content of sweet amino acid and branched chain amino acid, the content of aromatic amino acid and essential amino acid, the content of branched chain amino acid, aromatic amino acid and essential amino acid and the content of aromatic amino acid and essential amino acid. The principal component analysis showed that, the content of the primary seven amino acids could be composed into two principal components whose cumulative contribution rate could amount to 97.96%. The analysis of all kinds of amino acids’ content was carried according to the comprehensive ability of principal components to the primary characters, explaining the two principal components into comprehensive effect factors and sulfur amino acids effect factors and the principal component equation was established. The principal component score and the comprehensive score under different radiation doses could be calculated and the first one was 1.25 kGy. So the radiation dose of 1.25 kGy was better.