Abstract: When Trichoderma viride M100726 was mutated by ion implantation and 60Co mutagenesis to breed with high level cellulase, a strain named R16-1 which CMCase activity increased by 46.5% than the original strain M100726 was screened. the decomposing ability of construct inoculants made of R16-1 and an other strain (Aspergillus niger) was studied. Compared with the control, this inoculants could significantly promote colonization and propagation of mycete, accelerated the decomposition of straw; c/n, breaking power of rice straw and straw residual rate also had significant difference.