Abstract: As a typical specie in coastal wetland, Tamarix grows in intertidal and supratidal zone and is very important for protection of the coast and the improvement of the shoal. The "NAN HONG BEI LIU" wetland restoration project have been put forward clearly under the "13th Five-Year" plan of national economic and social development, which show that Tamarix plays a key role in coast protection. So, it is of great significance for Tamarix protection to estimate widespreadly the biomass by using remote sensing technology. In this paper, Taking Changyi Tamarix national special marine reserves as an example, GF-1 data which is developed by ourselves and in stiu measured data is used to establish Tamarix above-ground biomass (AGB) estimation model and choose optimal model, the model is applied in study area. The results show:(1) As one of five vegetation index, the correlation coefficient of RVI and Tamarix AGB is the highest, that is 0.686; (2) The determination coefficient of cubic polynomial model with RVI is the highest, it is 0.81. MRE and RMSE of model is the smallest, which is 4.7% and 0.05 kg/m² separately. (3) Combined with GF-1 image which is received in September 5, 2014 in the national special marine reserves, the model of cubic polynomial model with RVI is used to estimate AGB of Tamarix, the average AGB Tamarisk is 0.75 kg/m² and the total biomass of 15020 t in study area.