Dynamical behaviors near saddlenode bifurcation point in nervous system, in both deterministic and stochastic neuronal model, were simulated. The characteristics of neural firing induced by noise were revealed and identified to be a stochastic renewal process. Correspondingly, the autonomous stochastic resonance induced by noise was also studied. The results not only reveal the dynamics and characteristics of firing patterns near the saddlenode bifurcation point, but also provide practical method to identify the saddlenode bifurcation point in nervous system.