In order to adapt the ecological adaptation of fine root of gap border trees at preliminary stage,we studied the 34-year old Cupressus funebris plantation in central Sichuan hilly region,researched the first five orders of fine root dynamic rules of fine root morphology and biomass of different size of gaps (50 m²,100 m² and 150 m²) and C.funebris plantation (Ⅳ) at the first year.The main results were found as follows:(1)The fine root morphology and biomass of different root orders of C.funebris plantation have obvious change rule.The specific root length(SRL) and root length density(RLD) of the first order root were the largest,but the average diameter,average root length and biomass of the first order root were the smallest.The SRL and RLD of the fifth order root were the smallest,but the average diameter and biomass of the fifth order root were the largest.Fine root biomass and average diameter of C.funebris significantly increased with increase in order(P<0.05),while SRL and RLD decreased.(2)Compared with C.funebris plantation (Ⅳ),fine root of gap border trees(GBT) have insignificant average diameter,increase average root length and SRL,reduce RLD and biomass at the same root order.(3)GBT at the gap of 150 m² highly raised Matter Distribution of low root orders,with increasing SRL and decline RLD,to use underground forest gap in a more quality way.In conclusion,with the renew of herbs and shrubs the forest gaps have increased pressure of root to competition soil spaces,expansionary growth and heterogeneous exchange of fine root morphology and biomass.