Abstract: A strain of Hypsizygus marmoreus was mutagenized by nitrogen ion beam implantation method, the high-quality mutant strain X-004 was screened out by measuring the fruiting body yield, biological efficiency, content of ergosterol and conventional nutrition component, such as total saccharide, protein.X-004 had the highest fruiting body yield, ergosterol content, protein and crude fiber content in all the strains.The fruiting body yield of the strain was up to 139.22g, ergosterol content of the pileus was 4.228mg/g, 1.690mg/g of the stipe, protein and crude fiber content were 35.41% and 23.29% . The optimum rape straw cultivation formula for the strain: rape straw 35% , cottonseed hulls 35% , wheat bran 13% , sucrose 1% , superphosphate 1% , corn flour 5% , rice bran 10%.