A method for producing plant dye by high efficiency solid state fermentation of leaves of polygonum tinctorium includes the following steps: placing the leaves of polygonum tinctorium with separationof stalk and leaves into a microwave green color removing machine for removing green color; naturally drying the leaves of polygonum tinctorium, and uniformly spraying a fermentation accelerant on thesurface of the leaves of polygonum tinctorium; placing the leaves of polygonum tinctorium in a pulse solid state fermentation reactor, first subjecting to anaerobic fermentation, and opening pressurepulse and injecting damp air when the temperature is naturally raised to 40-60 DEG C, wherein the air humidity is 65%-90%, a pulse peak value is 0.2-0.3 MPa, a pulse valley value is 0.05-0.15 Mpa, apulse period is 30-120 minutes, and performing fermentation until the temperature is not raised by itself; and then drying the leaves by a microwave dryer. According to the method, the green color isquickly removed by the microwave, and the leaves of polygonum tinctorium after microwave green color removing can be naturally dried without requirement for climate and sites. At the same time, the fermentation accelerant is sprayed on the leaves of polygonum tinctorium before fermentation, and so, the fermentation period can be shortened, the pigment content is improved; and the pulse solid statefermentation reactor is cooperatively utilized, and therefore, the fermentation time can be greatly shortened, and the fermentation quality can be controlled. In a whole production process, no wateris discharge, and the method is environmentally friendly.