The axons of cerebellar Purkinje cells are the sole output of the cerebellar cortex. So it is important to study the spike propagation on the axons of cerebellar Purkinje cells. The morphology and function of cerebellar Purkinje cells mature rapidly in two to three weeks after birth. And the ability to fire spikes increases along with the development in cerebellar Purkinje cells. Whether the capacity of spike propagation on the axons also increase remains elusive. We studied this hypothesis by double-patch recordings in cerebellar Purkinje cells at PND 8(postnatal day) and 15. The spike propagation fidelity on the axons is higher at PND 15 than 8. Afterhyperpolarization(AHP) can increase spike propagation fidelity in cerebellar Purkinje cells at PND 8. Our data indicate that the ability to fire spikes and the capacity of spike propagation on the axons increase correspondingly along with the development.