Large - scale remotely sensed monitoring of carbon storage and carbon fluxes in forest ecosystem has become a hot topic in the backdrop of global warming caused by the continuous increase of CO_2 concentrations. The paper made an in - depth analysis of the two remote sensing based approaches for the estimation of forest carbon cycling:(1) estimating the forest aboveground biomass by using the remote sensing method,and then calculating the forest carbon storage indirectly,the change of which could be used to determine the CO_2 fluxes. This paper summarized the principles,advantages and disadvantages of various remote sensing methods for estimating forest biomass,and systematically reviewed the uncertainties of various models in estimating forest carbon storage in large areas.(2) monitoring quantitatively the forest ecosystem and atmospheric CO_2 fluxes based on the remote sensing data provided by meteorological or CO_2 greenhouse gas monitoring satellites,and then determining the changes in forest ecosystem carbon storage based on exchanges of CO_2 fluxes between forest ecosystem and atmosphere. For this approach,we summarized the mainstream data and methods that can be applied to monitor CO_2 fluxes between forest ecosystems and atmosphere and their strengths and weaknesses,systematically commented the progress of applying these dedicated data and approaches in the spatial - temporal variation characteristics monitoring of CO_2 fluxes and the estimation of forest carbon storage,analyzed the progress in the application of satellite data on CO_2 concentration,especially the data from China TanSat to the CO_2 column concentration inversion algorithm as well as the comparison,verification and assimilation of different data sources,and concluded the advantages of dedicated greenhouse gas remote sensing and observation satellite data in forest carbon storage and CO_2 fluxes monitoring. Finally,the paper prospected the use of remote sensing method for quantitative monitoring of forest ecosystem carbon cycle.