The current year twigs have less secondary tissue and are the most active part of the plant branching system. The variation along elevation gradients of current year twig traits and biomass allocation in woody plants are critical to understand the adaptation strategies of plant species to different habitats. This study was conducted in the headwater region of Minjiang River on the eastern edge of the Qinghai-Tibet Plateau, aimed to deal with the functional traits changes of twigs (stem length, stem diameter and specific stem length) and the biomass allocation in different organs (stem and leaf) of two dominant subalpine coniferous trees species (i.e., Picea purpura and Abies faxoniana). Plant traits and biomass allocation were compared at different altitude (3500-3550 m,3650-3700 m, 3800-3850 m), figuring out their biomass trade-off and growth strategies at different altitudes. The findings revealed that (1) the altitudinal interspecific difference of stem biomass was greater than their intraspecific difference, and the stem biomass at 3650-3700 m showed the greatest variation (128.4%). (2) Specific stem length of P. Purpurea existed a significantly positive correlation with altitude (P<0.05). Furthermore, there was a significantly negative correlation between stem biomass, leaf biomass, and altitude (P<0.05). A.faxoniana presented a significantly negative correlation between leaf biomass and altitude (P<0.05). (3) With the increase of altitude, the biomass allocation ratio of P. Purpurea stem decreased from 33.0% to 27.0%.The stem biomass allocation ratio of A. faxoniana increased from 23.0% to 28.0% (4) At 3500-3550 m and 3650-3700 m, there were allometric relationships of P. purpura between stem biomass and leaf biomass, stem length and stem diameter; There were allometric relationships of A.faxoniana between stem biomass and leaf biomass, stem length and stem diameter at 3500-3550 m, 3650-3700 m, and 3800-3850 m. The differences of two species in the biomass allocation ratio of their stem and related traits with altitude revealed that A. faxoniana was better adapted to high-altitude stress.