The study of signal transmission in neural models is helpful to investigate and model the transmission mechanism of biological neural systems, and realize the signal processing of cognition mechanism. We investigate the transmission of weak signals in a noisy one-way coupled Hodgkin-Huxley neural system. The results show that there is stochastic resonance and it helps to detect and transmit the signal. In addition, the coupling enables the signal transmission in the system. The efficiency of the signal transmission is increased with the increasing coupling strength. At some strength the firing of the elements will be in synchronization. What’s more, the optimal noise intensity of the receptor declines with the increase of the coupling strength, in the end will be equal to that of the driver. When the coupling strength is too high, the receptor will fire by itself. But the spikes will be suppressed by the increasing noise. It may be used to interpret the self action of neurons and the self adjusting in neural system. In addition, these results show that the noise and coupling are important to the transmission of weak signal in neural system. This study maybe helpful to interpret some phenomena in biological experiments.