The color of brown diamond from Mengyin of Shandong Province is caused by many factors. In order to verify the relationship between the brown color and the plastic deformation and analyze the characteristics of brown diamond under the transmission electron microscopy (TEM), the authors collected brown diamond samples from Mengyin Victory 1 rock tube, and made experiments on dislocation configuration of brown diamond, dislocation density and mineral energy spectrum under transmission electron microscopy (TEM) and X-ray energy spectrometer. The results show that there exists wafer nitrogen in the sample, demonstrating to some extent the dislocation configuration in darkened brown diamond of Shandong and suggesting that both the interaction between dislocations and the dislocation reaction types are very rich, and these characteristics are based on the premise of dislocation motion. Dislocation density shows in a sense that the diamond samples have a certain degree of plastic deformation, which provides some quantified reference for the connection between the brown color and the plastic deformation.