The protein nutrition of 60Coradiated mutant strain J5 of Agaricus blazei and its original strain J1 in different growing flushes were studied by non-biological evaluation. The results showed that essential amino acid index, biological value, nutritional index, score of ratio coefficient of amino acid, chemical score and amino acid score of fruit bodies of mutant strain J5 were 1.02%, 2.26%, 2.93%, 11.72%, 9.35% and 5.13% higher than that of strain J1 respectively. Four, five, five and six protein indexes respectively in the first, second, third and fourth growing flushes of mutant strains J5 were higher than that of its original strain J1. These results indicated that the protein nutrition of mutant strain J5 was higher than that of strain J1.