To reveal the decomposition mechanism of SF6 under negative DC partial discharge (PD), a PD hybrid numerical model of SF6 was constructed based on fluid dynamics and plasma chemical reaction, and then the electronic properties under the single PD current pulse were systematically discussed. The results show that the area with higher average electron energy is located near the tip of the needle, and the electron density is small in the cathode sheath and mainly concentrated close to the needle electrode. When PD current pulse rises, the electron density increases as the time of PD increases, and the center of the electron cloud is located on the axis of symmetry. When PD current pulse drops, with the development of the PD, it shows that the density of electron number decreases gradually and the electron cloud moves away from the axis of symmetry gradually, in addition, the generation and dissipation of electron almost occurs in the same area.