Abstract: In order to explore whether the coal gasification slag combined with oyster mushroom bran can be used as a sand modifier to improve the soil in the coal mine area, the coal gasification slag with a mass fraction of 10%, 20%, 30% and 40% of the soil in the coal mine area was mixed with 15 % mushroom bran and applied to the soil in the coal mine area. At the same time, the blank control （CK1, the coal mine soil） and the coal mine soil with mushroom bran （CK2） were set up. Under the condition of soil fallow state, the soil enzyme activity of each treatment was measured every 7 days. The results showed that the soil enzyme activity of CK2 was higher than that of CK1 at 0, 7 and 14 d. The soil enzyme activity of each coal gasification slag treatment was higher than that of CK2, and the soil enzyme activity under the treatment of 30% coal gasification slag combined with 15% oyster mushroom bran （T3） was at the highest level. Compared with CK2, except that catalase did not reach a significant level at 7 d, other enzyme activities of T3 were significantly increased at any time （P < 0.05）. In summary, the application of 30% coal gasification slag with 15% oyster mushroom bran could promote soil enzyme activity to the greatest extent.

Key words: coal gasification slag, oyster mushroom bran, soil enzyme activity, soil improvement, coal mine area