Abstract: Some sufficient criterias about the existence and uniqueness of a ω-periodic solution are obtained under the assumption of that each output response is bounded and satisfies Lipschitz condition for Hopfield neural network, when all input signals are continuously ω-periodic functions and the network parameters satisfy suitable conditions, by means of the method of a suitable Lyapunov functional. And it is proved that all other solutions converge exponentially to the above ω-periodic solution. An intuitive explain of the above new criteras is given in the final example.