To explore the influence of nano-graphite powder on the geotechnical engineering properties of regional red clay, the triaxial test was designed by orthogonal experiment. Nano-graphite powder was added to Guilin red clay by the dosage ratio of 0%, 0.5%, 1% and 2% respectively, through the consolidation undrained test, combined with the characteristics of the main stress differential strain curve, using Excel for nonlinear programming, the total stress shear strength index of each sample was obtained, and the Mohr failure envelope was plotted. The results show that the addition of nano-graphite powder has certain influence on the stress-strain curve of red clay. The concrete manifestation is the approximate ideal ductile characteristics at each confining pressure, and its shape shows an approximate hyperbola with obvious peak. The shear strength of modified red clay can be described by the linear Mohr-Coulomb criterion. The parameters of internal friction angle are basically the same with the increase of the content of nano-graphite powder, while the cohesion parameters have the characteristics of first increasing and then decreasing with the increase of the content.