Abstract:The efficacy of complex strains between 6 different Trichoderma spp · strains to control rice seedling blight was reported. The result showed that in seedling emergence there was no significantly difference among the complex strains, single strain and control except two complex strains(943110+9440-4 and 9452-3+9524-5). However, the efficacy of treatments to control rice seeding blight were significantly different. Some complex strains showed good effectiveness (better than the two original single strains), some showed the efficacy of complex strains were between the two original single strains and some did not show any effectiveness. The best one was 9440-4+9524-5 and its efficacy was 90. 82%.