Abstract: First, the change rules of mixed-mode oscillations in the model were explored, and period-doubling bifurcation diagram and period-adding bifurcation diagram in the interspike interval sequences of the small amplitude oscillations were obtained through the time series of the potential. And the stepped change in the spike counts were also investigated. Then, the chaotic phenomena in array and non-array of mixed-mode oscillations were analyzed in the region between the "steps" of the parameters. Finally, the influence of other factors in the circuit model on the generation of mixed-mode in the system were discussed. By using the interspike intervals bifurcation diagram between the small oscillations, it is found that the frequency and intensity of weak disturbance can change the firing patterns of the circuit system.