The invention discloses a digital micromirror device (DMD) based method and a digital micromirror device (DMD) based system for generating broadband dynamic optical scene. One piece digital grayscale image is divided into n binary digital images by a figure computer according to binary method; the n binary digital images are converted into n binary optical images by n sets of DMD-based dynamic image convertors; the beams of the n binary optical images are combined by beam splitters and then are imaged on an imaging surface by an imaging optical system; the intensity of light source on any onesurface which is perpendicular to an optical axis and is positioned between the last beam splitter and the imaging optical system is made to meet the following equation through designing the reflectivity and the transmittance of the beam splitters and selecting the light source intensity of the DMD-based dynamic image convertors: E(i+1)/Ei=2, wherein i is more than or equal to 1 and is less than or equal to n-1, and a dynamic optical scene with 2n grayscales are generated. The digital micromirror device (DMD) based method and the digital micromirror device (DMD) based system for generating broadband dynamic optical scene can be used for high frame-frequency large grayscale staring imaging and the semi-physical simulation test of a scanning imaging optical sensor.