To improve the security of secret communication in ring networks, we analyze the effect of time delay interference on a ring network synchronization. Firstly, according to the topology of the ring network, the mathematical model of the ring network disturbed by time-varying delay is constructed. Then, based on the Lyapunov stability method, an adaptive controller is designed to control the ring network, and realize the modified function projection synchronization of the ring network with no time-delay, constant-delay and time-varying-delay, which shows that the adaptive controller is universal. At last, the correctness of the theoretical analysis is verified by numerical simulation, and it is found that the synchronization ability of the ring network is reduced by time-delay interference, the greater the delay, the worse the synchronization ability and the longer the time needed to achieve synchronization.