From the viewpoint of membrane potential and the ISIs, the dynamic characteristics in the bursting of the model were obtained by researching the model of excitatory interneuron in the Pre-B?tzinger Complex. Through researching the different values of neuroelectrophysiologic parameters such as membrane capacitance, equilibrium potential, specific conductance of ion channel and so on, we found some different period bifurcation phenomena of ISIs sequence, for example, period adding bifurcation and period doubling bifurcation. Moreover, the model is helpful in understanding the conversion mode of bursting and the encoding characteristics of interneuron in the Pre-Btzinger Complex, and if is also beneficial to researching the impact of these bursting characteristics on respiratory rhythm.