The invention discloses a winter wheat canopy moisture content monitoring model establishing method based on a spectral parameter. In the invention, according to winter wheat canopy spectral reflectivity of each growth period and plant canopy moisture content data under different water treatments, a relationship between basic transformation of spectral information and a "three-sided" parameter ona plant canopy moisture content is analyzed, a suitable model combination considering a characteristic of each growth period and possessing high precision is provided, and a principal component estimation model of the plant canopy moisture content, which integrates the basic transformation of the spectral information, the "three-sided" parameter and other independent variables, is constructed. Effects of a spectrum monitoring birth period constraint and other background noises are broken through, and a theoretical basis and technical support are provided for winter wheat plant moisture contenthyperspectral accurate diagnosis.