Abstract: Pot experiment with discarded greenish mudstone from large opencut coal mine as test soil was conducted to study the application of ectomycorrhizal fungi in the ecological reconstruction of fragile ecological belt of large opencut coal mine of Huolinhe region, Inner Mongolia. The result showed that after the greenish mudstone was inoculated with ectomycorrhizal fungi, the rates of seedling infection and survival were 1.21～2.78 higher in treatment with no fertilizer application than in that with fertilizer application. The test ectomycorrhizal inoculum 010, Aand Bhad a stronger regulation ability in infertile and low penetration coefficient soil. The ammonification of the mudstone could improve its physical and chemical properties, but shorten the survival duration of seedling on account of the accumulation of ammonia and phosphorus in it.