A method for remote sensing estimation of a weight ratio of green plants to withered plants of grassland comprises the following steps: acquiring grassland space distribution data of a research area; positioning ground sampling points; determining the weight ratio of green plants to withered plants at every sampling point; determining a spectral index for estimating the green plants to withered plants; determining a model for remote sensing estimation of the weight ratio of green plants to withered plants of the research area; calculating the spectral index to be estimated of the research area; carrying out remote sensing estimation on the weight ratio of green plants to withered plants, with the date to be estimated, of the research area; and carrying out dynamic remote sensing estimation researches on the weight ratio of green plants to withered plants of the grassland in the research area. The method allows a spectral waveband sensitive to the green plants and withered plants to be found through a remote sensing technology, constructs the spectral index for estimating the weight ratio of green plants to withered plants, realizes remote sensing estimation of a weight ratio of green plants to withered plants of the grassland, and provides technical support for ecologic researches and development strategy of the grassland.