Both time delay and coupling form are the most important factors in neural networks. The properties of firing rate oscillation and cluster synchronization induced by time delay are studied in random network of different coupling neurons. In previous work, the firing rate oscillation of cortical network was observed at the presence of three factors (time delay, weak sinusoidal signal, and noise). Here, we found that the firing rate oscillation can be induced only by the time delay, and the spike train can be propagated at a certain interval time, which is consistent with the value of delay time...