Abstract: In order to explore the effect of trichoderma on the decomposition and revegetation of coal gangue,the tri-choderma with low (0. 03% ),medium (0. 15% ),high (0. 30% ) doses was applied in coal gangue decomposition experiments and alfalfa pot experiments to determine coal gangue decomposition rate,alfalfa fresh weight and root char-acteristics,as well as the physical,chemical,and microbiological properties of coal gangue matrix. The results showed that trichoderma could increase the root length,root-shoot ratio,root volume and number of lateral roots of alfalfa. Tri-choderma could significantly change the mechanical com-position of coal gangue,and fine gravel was the main compo-nent of weathering. With the increase of the dose of trichoderma,the fine gravel had a tendency to be further decom-posed into coarse sand and medium sand. Trichoderma promoted the fine microscopic structure of coal gangue. Tri-choderma could also increase avail-able nitrogen,available phosphorus,available potassium content,microbial biomass carbon,nitrogen,phos-phorus and catalase,urease,phosphatase activity of coal gangue matrix,thereby promoting the decomposing and revegetation effect of coal gangue. In general,the low dose trichoderma did not obviously promote the revegetation effect of coal gangue,the medium and high dose of trichoderma had the significant effect,which increased the decomposition rate of coal gangue and alfalfa fresh weight by 44. 24% ,38. 86% and 31. 33% ,22. 04% ,respec-tively. Medium dose trichoderma had the best effect on the decomposition and revegetation of coal gangue. Therefore, the medium dose of trichoderma can be used for the revegetation of coal gangue.