Fine roots play an important role in the function of individual plants. Recent studies indicated large heterogeneity in architecture, morphology, anatomy, physiology, and longevity within the fine root pool which can be systematically described by branching order. To date, while it is remarkable how little we know about the architecture and morphology in fine roots of subtropical evergreen broad-leaf forest. So in this study intact fine root segments of six dominant tree species (Cinnamomum micranthum, CIM; Tsoongiodendron odorum Chun, TOC; Cinnamomum chekiangense, CIC; Castanopsis fabri, CAF; Altingia gracilipes, ALG; and Castanopsis carlesii, CAC) were collected by excavation in an evergreen broadleaved forest located at the Wanmulin Nature Reserve, Jian'ou, Fujian province. Individual roots were dissected according to the branching order, starting from the distal end of the root system that was numbered as the first order and then increasing sequentially with each branch from the first order to fifth order roots. Then, fine root samples were scanned by the Espon scanner, used Win-RHIZO system to analyze root architecture and morphology. We attempted to address the following questions: (1) the effect of root order and tree species on fine root architecture and morphology; and (2) the relationship between specific root length, tissue density and diameter across root order and tree species. The result showed that: for CIM, ALG and CAC, the branching ratios (Rb) was higher between the first two root orders (over 4) than between the other orders (about 3); while for TOC, CIC and CAF, Rb were higher between the third and forth orders than between the other orders (about 3), with the highest Rb value of 8.65 between the third and forth orders of CIC. For all species, 70% to 90% of total root number comprised the first two orders. Root diameter, length, and tissue density increased and specific root length (SRL) decreased with increase in order for all species. Though there was no consistent changed with root order, root biomass was mainly concentrated in the higher root orders. The ANOVA demonstrated that both tree species (P<0.05 for all cases) and tree species ×branching level (P<0.01 for all cases) had significant effect on Rb. The branching level had significant effect on Rb for CIC and CAC (P<0.01) and for the other four species (P<0.05). Tree species had significant effect on root length, diameter, biomass (P<0.01) and SRL (P<0.05), but had no significant effect on tissue density (P>0.05). The tree species ×root order interaction had significant effect on root length, diameter, biomass (P<0.01) and tissue density (P<0.05), but had no significant effect on SRL (P<0.01). Though root order had no consistent effect on root length, diameter, SRL and biomass, it had significant effect on tissue density for all species (P<0.01). The variations in SRL of the first to the forth orders among species were mainly caused by tissue density, while those of the fifth order caused by root diameter. A trade-off between root diameter and tissue density occured in the first order. For individual species, changes in root number, diameter, length, SRL, tissue density and biomass with root order can be represented by exponential, linear, quadratic, cubic or power functions.