Abstract: The soi1 humus and soil structure were observed by planting Slenderstalk ahingia under the canopy of sprout of Chinese fir on mixed stands of Chinese fir and broadleaved tree．The results indicate that the contents of soil organic matter and humus are increased，the H_A／H_F and E₄ value of humus are raised and E₄／E₆ value is descended，loosely and tightly combined humus contents and its ratio are ascended and the activation of son hunms is strengthened，the soil structure and moisture properties have been improved obviously after the transformed mixed stand of Slenderstalk ahingia．