Aboveground biomass (AGB) is an important indicator of grassland state. Remote sensing estimation method of grassland biomass can provide important decision support for decision-makers and relevant personnel on grassland management, such as the rational development and utilization of grassland resources, the local ecological environment protection and the rational development of animal husbandry. In this study, based on Landsat 8 and Sentinel-2 A/B satellites data, PROSAILH radiative transfer model (RTM) and look up table (LUT) algorithm were applied to temporally retrieve and map the grassland AGB in Qinghai Province from September 2019 to August 2020, an important graziery region in China. Further analysis on the relation between the AGB and meteorological data showes that the precipitation and air temperature in Qinghai is consistent with the average biomass dynamic, indicating the considerable effect of the meteorological factors on the AGB in this region.