Abstract: The fine root production and turnover are important parts of the terrestrial ecosystem carbon cycle, but few researches were conducted on fine root turnover and its contribution to soil carbon cycling of Tamarix ramosissima Lour. community in arid ecosystem. In this research, a typical native T. ramosissima community was selected, and the continuous soil drilling method and fine root bag method were used to investigate the monthly fine root dynamic, production and fine root turnover from May to October, 2010 (the whole growing season). The results showed that the soil water content increased with the depth of soil, while the soil organic carbon decreased. The mean fine root biomass in the community was 93.10 g·m-2 and the live fine root biomass and dead fine root biomass were 73% and 27% of total fine root biomass in the community, respectively. The dynamics of biomass and necromass of fine root in the T. ramosissima community showed the same pattern in the growing season, the biomass slightly increased from May to September, and then decreased. The fine root biomass in the community increased at first, and then reduced gradually with the increase of soil depth. The fine root biomass in 0－40 cm soil layer was the largest parts, with 88.01% of total fine root biomass for the community. The fine root decomposition rate showed a sharp decline to the minimum then declined steadily for the community, and the annual fine root decomposition rate was 51.24% for the community. 351 days and 1 359 days were needed to reach half decomposition and 95% decomposition for the community. The net productivity of fine root in the community was 118.81 g·m-2, the fine root annual turnover rate was 1.98 times·a-1, and the annual input from fine root mortality to underground soil organic carbon was 42.68 g·m-2·a-1. These results showed that the annual input from fine root turnover to underground soil organic carbon counted for only a small portion of the soil organic carbon, however, in a long time, the fine root carbon is a crucial for soil carbon pool in arid area.