Abstract:The results showed that successive cultivating chinese fir in the same land can cause degradation of forest land's fertility an degraded extent of its soil produetivity is related to growth periodicity of pre-stubble forest. When frist stubble forests for chinese fir have short periodicity(i. e. 14 years),the chinese fir continously-cultivated in the secondly-cultivated soil have a fair good growth vigour; when have long periodicity(i. e. 24 years),the same kind of juvenile chinese fir have a extremely inferior growth vigour,and after-fertilizing can not promote recovery of juvenile chinese fir's growth. It was because the root system of juvenile chinese fir were poisoned by toxic substance from soils,which further cause their rot and make it no uptaking nutrient from the soil. To solve problems from degradation of soil productivity owing to successive cultivation for chinese fir,their suggestion is to take bioengineering measure.