The invention relates to a building method of a solar agricultural greenhouse, which is characterized in that a steel pipe structure is adopted; an sandwiched cement board composite heat-insulation glass wool is used as a wall body; an all-glass wall body is adopted at a sunny side; glass with a light-focusing magnifier is adopted at a nightside; a reflector face is arranged outside the nightside; heat is accumulated by utilizing solar light focusing and reflecting light focusing; a heating device is arranged underground; a heat absorber is filled with a phase-change heat-conducting medium; and heating pipelines are uniformly distributed under the ground of the solar agricultural greenhouse so as to ensure that the integral temperature of the solar agricultural greenhouse is more than 15 DEG C higher than that of the ground. The building method provided by the invention is favorable for sufficiently utilizing and uniformly distributing heat energy, can be applied to production in a standardized, universalized and industrialized way and widely applied to the building and the improvement of the solar agricultural greenhouse, and has an obvious energy-saving effect.