This paper presents Jacobi stability analysis of 23 simple chaotic systems with only one Lyapunov stable equilibrium by Kosambi–Cartan–Chern theory, and analyzes the chaotic behavior of these systems from the geometric viewpoint. Different from Lyapunov stability, the unique equilibrium for each system is always Jacobi unstable. Moreover, the dynamical behaviors of deviation vector near equilibrium are discussed to reveal the onset of chaos for these 23 systems and show geometrically the coexistence of unique Lyapunov stable equilibrium and chaotic attractor for each system. The obtaining results show that these chaotic systems are not robust to small perturbations of the equilibrium, indicating that the systems are extremely sensitive to the internal environment. This reveals that the chaotic flows generated by these systems may be related to Jacobi instability of the equilibrium.