Abstract: According to the influencing factors of red clay shear strength, I used the triaxial test method to unconsolidate the undrained test, and used the orthogonal test table to arrange the test plan. After the test, the microstructure of the sample after the test was tested. The comprehensive balance method was used to analyze the sensitivity of factors such as moisture content, mix ratio, and confining pressure to shear strength. The results show that the Nano-graphite powder content and water content are all significant factors affecting the shear strength parameters of red clay under certain dry density conditions. With the increase of the water content and the Nano-graphite powder incorporation ratio, the shear strength increases first and then decreases. The stress-strain curve of Nano graphite powder red clay has obvious peak stress, which is characterized by strain hardening. The micro-improved mechanism shows that the addition of Nano-graphite powder changes the adhesion of kaolinite and other clay minerals, resulting in re-agglomeration of graphite powder in the pores, reducing the porosity, and increasing the cementation of soil particles.