Abstract: Using 20 varieties and radiated mutants of Lentinus giganteus as materials, the multiple correlation, regression relation and cluster analysis between protein content and 17 amino acids contents were conducted to provide scientific basis for breeding of L. giganteus. The results show that among the new radiated mutants of L. giganteus, Fu105 contains the highest amounts of Asp, Thr, Gly, Ala, Cys, Val, Ile, Phe and protein in its fruit body, which is significantly higher than some tested varieties or new radiated mutants. There exists a significant positive correlation between most amino acid content and protein content, of which 5 amino acids have a linear, 10 have conic, and 2 have cubic relationship with protein. Trough systematic cluster analysis, the protein content and 17 amino acids are divided into 4 groups. The optimization of typical characters, such contents of Arg, Leu, Cys and Met, in each group could improve the efficiency of protein composition in L. giganteus breeding.